shorewall-nesting

title: shorewall-nesting(5)

summary: Shorewall Nested Zones

text:
# shorewall-nesting(5)

## NAME
nesting - Shorewall Nested Zones

## SYNOPSIS
child-zone[:parent-zone[,parent-zone]...]

## DESCRIPTION
In shorewall-zones[1](5), a zone may be declared to be a sub-zone of one or more other zones using the above syntax. The child-zone may be neither the firewall zone nor a vserver zone. The firewall zone may not appear as a parent zone, although all vserver zones are handled as sub-zones of the firewall zone.

Where zones are nested, the CONTINUE policy in shorewall-policy[2](5) allows hosts that are within multiple zones to be managed under the rules of all of these zones.

## EXAMPLE
/etc/shorewall/zones:

```
        #ZONE    TYPE        OPTION

        fw       firewall

        net      ipv4

        sam:net  ipv4

        loc      ipv4
```

/etc/shorewall/interfaces:

```
        #ZONE     INTERFACE     BROADCAST     OPTIONS

        -         eth0          detect        dhcp,norfc1918

        loc       eth1          detect
```

/etc/shorewall/hosts:

```
        #ZONE     HOST(S)                     OPTIONS

        net       eth0:0.0.0.0/0

        sam       eth0:206.191.149.197
```

/etc/shorewall/policy:

```
        #SOURCE      DEST        POLICY       LOG LEVEL

        loc          net         ACCEPT

        sam          all         CONTINUE

        net          all         DROP         info

        all          all         REJECT       info
```

The second entry above says that when Sam is the client, connection requests should first be processed under rules where the source zone is sam and if there is no match then the connection request should be treated under rules where the source zone is net. It is important that this policy be listed BEFORE the next policy (net to all). You can have this policy generated for you automatically by using the IMPLICIT_CONTINUE option in shorewall.conf[3](5).

Partial /etc/shorewall/rules:

```
        #ACTION   SOURCE    DEST            PROTO    DPORT

        ...

        DNAT      sam       loc:192.168.1.3 tcp      ssh

        DNAT      net       loc:192.168.1.5 tcp      www

        ...
```

Given these two rules, Sam can connect to the firewall's internet interface with ssh and the connection request will be forwarded to 192.168.1.3. Like all hosts in the net zone, Sam can connect to the firewall's internet interface on TCP port 80 and the connection request will be forwarded to 192.168.1.5. The order of the rules is not significant. Sometimes it is necessary to suppress port forwarding for a sub-zone. For example, suppose that all hosts can SSH to the firewall and be forwarded to 192.168.1.5 EXCEPT Sam. When Sam connects to the firewall's external IP, he should be connected to the firewall itself. Because of the way that Netfilter is constructed, this requires two rules as follows:

```
        #ACTION   SOURCE    DEST            PROTO    DPORT

        ...

        ACCEPT+   sam       $FW             tcp      ssh

        DNAT      net       loc:192.168.1.3 tcp      ssh

        ...
```

The first rule allows Sam SSH access to the firewall. The second rule says that any clients from the net zone with the exception of those in the “sam” zone should have their connection port forwarded to 192.168.1.3. If you need to exclude more than one zone, simply use multiple ACCEPT+ rules. This technique also may be used when the ACTION is REDIRECT.

Care must be taken when nesting occurs as a result of the use of wildcard interfaces (interface names ends in '+').

Here's an example. /etc/shorewall/zones:

/etc/shorewall/interfaces:

```
        #ZONE    INTERFACE      BROADCAST        OPTIONS

        net      ppp0

        loc      eth1

        loc      ppp+

        dmz      eth2
```

Because the net zone is declared before the loc zone, net is an implicit sub-zone of loc and in the absence of a net->... CONTINUE policy, traffic from the net zone will not be passed through loc->... rules. But DNAT and REDIRECT rules are an exception!

•DNAT and REDIRECT rules generate two Netfilter rules: a 'nat' table rule that rewrites the destination IP address and/or port number, and a 'filter' table rule that ACCEPTs the rewritten connection.

•Policies only affect the 'filter' table.

As a consequence, the following rules will have unexpected behavior:

```
        #ACTION     SOURCE               DEST      PROTO        DPORT

        ACCEPT      net                  dmz       tcp          80

        REDIRECT    loc                  3128      tcp          80
```

The second rule is intended to redirect local web requests to a proxy running on the firewall and listening on TCP port 3128. But the 'nat' part of that rule will cause all connection requests for TCP port 80 arriving on interface ppp+ (including ppp0!) to have their destination port rewritten to 3128. Hence, the web server running in the DMZ will be inaccessible from the web.

The above problem can be corrected in several ways.

The preferred way is to use the ifname pppd option to change the 'net' interface to something other than ppp0. That way, it won't match ppp+.

If you are running Shorewall version 4.1.4 or later, a second way is to simply make the nested zones explicit:

```
        #ZONE    TYPE        OPTION

        fw       firewall

        loc      ipv4

        net:loc  ipv4

        dmz      ipv4
```

If you take this approach, be sure to set IMPLICIT_CONTINUE=No in shorewall.conf.

When using other Shorewall versions, another way is to rewrite the DNAT rule (assume that the local zone is entirely within 192.168.2.0/23):

```
        #ACTION     SOURCE                 DEST      PROTO      DPORT

        ACCEPT      net                    dmz       tcp        80

        REDIRECT    loc:192.168.2.0/23     3128      tcp        80
```

Another way is to restrict the definition of the loc zone:

/etc/shorewall/interfaces:

```
        #ZONE    INTERFACE      BROADCAST        OPTIONS

        net      ppp0

        loc      eth1

        -        ppp+

        dmz      eth2
```

/etc/shorewall/hosts:

```
        #ZONE    HOST(S)             OPTIONS

        loc      ppp+:192.168.2.0/23
```

## FILES
/etc/shorewall/zones

/etc/shorewall/interfaces

/etc/shorewall/hosts

/etc/shorewall/policy

/etc/shorewall/rules

/etc/shorewall6/zones

/etc/shorewall6/interfaces

/etc/shorewall6/hosts

/etc/shorewall6/policy

/etc/shorewall6/rules

## SEE ALSO
shorewall(8), shorewall-accounting(5), shorewall-actions(5), shorewall-blacklist(5), shorewall-hosts(5), shorewall_interfaces(5), shorewall-ipsets(5), shorewall-maclist(5), shorewall-masq(5), shorewall-nat(5), shorewall-netmap(5), shorewall-params(5), shorewall-policy(5), shorewall-providers(5), shorewall-proxyarp(5), shorewall-rtrules(5), shorewall-routestopped(5), shorewall-rules(5), shorewall.conf(5), shorewall-secmarks(5), shorewall-tcclasses(5), shorewall-tcdevices(5), shorewall-mangle(5), shorewall-tos(5), shorewall-tunnels(5), shorewall-zones(5)

## NOTES
1.

shorewall-zones

https://shorewall.org/manpages/shorewall-zones.html

2.

shorewall-policy

https://shorewall.org/manpages/shorewall-policy.html

3.

shorewall.conf

https://shorewall.org/manpages/shorewall.conf.html


shorewall-netmap

package: shorewall

title: shorewall-netmap(5)

summary: Shorewall NETMAP definition file

text:
# shorewall-netmap(5)

## NAME
netmap - Shorewall NETMAP definition file

## SYNOPSIS
/etc/shorewall[6]/netmap

## DESCRIPTION
This file is used to map addresses in one network to corresponding addresses in a second network.

Warning

To use this file, your kernel and iptables must have NETMAP support included.

The columns in the file are as follows (where the column name is followed by a different name in parentheses, the different name is used in the alternate specification syntax).

TYPE - {DNAT|SNAT}

If DNAT, traffic entering INTERFACE and addressed to NET1 has its destination address rewritten to the corresponding address in NET2. If SNAT, traffic leaving INTERFACE with a source address in NET1 has it's source address rewritten to the corresponding address in NET2.

NET1 - network-address

Network in CIDR format (e.g., 192.168.1.0/24). Beginning with Shorewall 4.4.24, exclusion[1] is supported.

INTERFACE - interface

The name of a network interface. The interface must be defined in shorewall-interfaces[2](5). Shorewall allows loose matches to wildcard entries in shorewall-interfaces[2](5). For example, ppp0 in this file will match a shorewall-interfaces[2](8) entry that defines ppp+.

NET2 - network-address

Network in CIDR format

NET3 (Optional) - network-address

Added in Shorewall 4.4.11. If specified, qualifies INTERFACE. It specifies a SOURCE network for DNAT rules and a DESTINATION network for SNAT rules.

PROTO - protocol-number-or-name

Optional -- added in Shorewall 4.4.23.2. Only packets specifying this protocol will have their IP header modified.

DPORT - port-number-or-name-list

Optional - added in Shorewall 4.4.23.2. Destination Ports. A comma-separated list of Port names (from services(5)), port numbers or port ranges; if the protocol is icmp, this column is interpreted as the destination icmp-type(s). ICMP types may be specified as a numeric type, a numeric type and code separated by a slash (e.g., 3/4), or a typename. See https://shorewall.org/configuration_file_basics.htm#ICMP[3]. If the protocol is ipp2p, this column is interpreted as an ipp2p option without the leading "--" (example bit for bit-torrent). If no PORT is given, ipp2p is assumed.

An entry in this field requires that the PROTO column specify icmp (1), tcp (6), udp (17), sctp (132) or udplite (136). Use '-' if any of the following field is supplied.

This column was formerly labelled DEST PORT(S).

SPORT - port-number-or-name-list

Optional -- added in Shorewall 4.4.23.2. Source port(s). If omitted, any source port is acceptable. Specified as a comma-separated list of port names, port numbers or port ranges. An entry in this field requires that the PROTO column specify tcp (6), udp (17), sctp (132) or udplite (136). Use '-' if any of the following fields is supplied.

This column was formerly labelled SOURCE PORT(S).

## FILES
/etc/shorewall/netmap

/etc/shorewall6/netmap

## SEE ALSO
https://shorewall.org/netmap.html[4]

https://shorewall.org/configuration_file_basics.htm#Pairs[5]

shorewall(8)

## NOTES
1.

exclusion

https://shorewall.org/manpages/shorewall-exclusion.html

2.

shorewall-interfaces

https://shorewall.org/manpages/shorewall-interfaces.html

3.

https://shorewall.org/configuration_file_basics.htm#ICMP

https://shorewall.org/configuration_file_basics.htm#ICMP

4.

https://shorewall.org/netmap.html

https://shorewall.org/netmap.html

5.

https://shorewall.org/configuration_file_basics.htm#Pairs

https://shorewall.org/configuration_file_basics.htm#Pairs


shorewall-params

title: shorewall-params(5)

summary: Shorewall parameters file

text:
# shorewall-params(5)

## NAME
params - Shorewall parameters file

## SYNOPSIS
/etc/shorewall[6]/params

## DESCRIPTION
Assign any shell variables that you need in this file. The file is always processed by /bin/sh so the full range of shell capabilities may be used.

It is suggested that variable names begin with an upper case letter to distinguish them from variables used internally within the Shorewall programs

The following variable names must be avoided. Those in bold font must be avoided in all Shorewall versions; those in regular font must be avoided in versions prior to 4.4.8.

Any option from shorewall.conf[1]

(5)

COMMAND

CONFDIR

DEBUG

ECHO_E

ECHO_N

EXPORT

FAST

FILEMODE

HOSTNAME

IPT_OPTIONS

NOROUTES

PREVIEW

PRODUCT

PROFILE

PURGE

RECOVERING

RESTOREPATH

RING_BELL

SHAREDIR

Any name beginning with SHOREWALL_ or

SW_

STOPPING

TEST

TIMESTAMP

USE_VERBOSITY

VARDIR

VERBOSE

VERBOSE_OFFSET

VERSION

Example params file:

```
NET_IF=eth0
NET_BCAST=130.252.100.255
NET_OPTIONS=routefilter
```

Example shorewall-interfaces[2](5) file.

```
ZONE    INTERFACE       BROADCAST       OPTIONS
net     $NET_IF         $NET_BCAST      $NET_OPTIONS
```

This is the same as if the interfaces file had contained:

```
ZONE    INTERFACE       BROADCAST       OPTIONS
net     eth0            130.252.100.255 routefilter
```

## FILES
/etc/shorewall/params

/etc/shorewall6/params

## SEE ALSO
https://shorewall.org/configuration_file_basics.htm#Variables[3]

shorewall(8)

## NOTES
1.

shorewall.conf

https://shorewall.org/manpages/shorewall.conf.html

2.

shorewall-interfaces

https://shorewall.org/manpages/shorewall-interfaces.html

3.

https://shorewall.org/configuration_file_basics.htm#Variables

https://shorewall.org/configuration_file_basics.htm#Variables


shorewall-policy

title: shorewall-policy(5)

summary: Shorewall policy file

text:
# shorewall-policy(5)

## NAME
policy - Shorewall policy file

## SYNOPSIS
/etc/shorewall[6]/policy

## DESCRIPTION
This file defines the high-level policy for connections between zones defined in shorewall-zones[1](5).

Important

The order of entries in this file is important

This file determines what to do with a new connection request if we don't get a match from the shorewall-blrules[2](5) or shorewall-rules[3](5) files. For each source/destination pair, the file is processed in order until a match is found ("all" will match any source or destination).

Important

Intra-zone policies are pre-defined

For $FW and for all of the zones defined in shorewall-zones[1](5), the POLICY for connections from the zone to itself is ACCEPT (with no logging or TCP connection rate limiting) but may be overridden by an entry in this file. The overriding entry must be explicit (specifying the zone name in both SOURCE and DEST) or it must use "all+" (Shorewall 4.5.17 or later).

Similarly, if you have IMPLICIT_CONTINUE=Yes in shorewall.conf[4](5), then the implicit policy to/from any sub-zone is CONTINUE. These implicit CONTINUE policies may also be overridden by an explicit entry in this file.

The columns in the file are as follows (where the column name is followed by a different name in parentheses, the different name is used in the alternate specification syntax).

SOURCE - zone[,...[+]]|$FW|all[+][!ezone[,...]]

Source zone. Must be the name of a zone defined in shorewall-zones[1](5), $FW, "all" or "all+". Support for all+ was added in Shorewall 4.5.17. all does not override the implicit intra-zone ACCEPT policy while all+ does.

Beginning with Shorewall 5.0.12, multiple zones may be listed separated by commas. As above, if '+' is specified after two or more zone names, then the policy overrides the implicit intra-zone ACCEPT policy if the same zone appears in both the SOURCE and DEST columns.

Beginning with Shorewall 5.2.3, a comma-separated list of excluded zones preceded by "!" may follow all or all+.

DEST - zone[,...[+]]|$FW|all[+][!ezone[,...]]

Destination zone. Must be the name of a zone defined in shorewall-zones[1](5), $FW, "all" or "all+". If the DEST is a bport zone, then the SOURCE must be "all", "all+", another bport zone associated with the same bridge, or it must be an ipv4 zone that is associated with only the same bridge. Support for "all+" was added in Shorewall 4.5.17. "all" does not override the implicit intra-zone ACCEPT policy while "all+" does.

Beginning with Shorewall 5.0.12, multiple zones may be listed separated by commas. As above, if '+' is specified after two or more zone names, then the policy overrides the implicit intra-zone ACCEPT policy if the same zone appears in both the SOURCE and DEST columns.

Beginning with Shorewall 5.2.3, a comma-separated list of excluded zones preceded by "!" may follow all or all+.

POLICY - {ACCEPT|DROP|REJECT|BLACKLIST|CONTINUE|QUEUE|NFQUEUE[([queuenumber1[:queuenumber2[c]][,bypass]]|bypass)]|NONE}[:{[+]policy-action[:level][,...]|None}]

Policy if no match from the rules file is found. If the policy is neither CONTINUE nor NONE then the policy may be followed by ":" and one of the following:

1.The word "None" or "none". This causes any default action defined in shorewall.conf[4](5) to be omitted for this policy.

2.The name of an action with optional parameters enclosed in parentheses. The action will be invoked before the policy is enforced.

Actions can have parameters specified.

Beginning with Shorewall 4.5.10, the action name can be followed optionally by a colon and a log level. The level will be applied to each rule in the action or body that does not already have a log level.

Beginning with Shorewall 5.1.2, multiple action[:level] specification may be listeded, separated by commas. The actions are invoked in the order listed. Also beginning with Shorewall 5.1.2, the policy-action list can be prefixed with a plus sign ("+") indicating that the listed actions are in addition to those listed in the related _DEFAULT setting in shorewall.conf[4](5).

Possible policies are:

ACCEPT

Accept the connection.

DROP

Ignore the connection request.

REJECT

For TCP, send RST. For all other, send an "unreachable" ICMP.

BLACKLIST

Added in Shorewall 5.1.1 and requires that the DYNAMIC_BLACKLIST setting in shorewall.conf[4](5) specifies ipset-based dynamic blacklisting. The SOURCE IP address is added to the blacklist ipset and the connection request is ignored.

QUEUE

Queue the request for a user-space application such as Snort-inline.

NFQUEUE

Queue the request for a user-space application using the nfnetlink_queue mechanism. If a queuenumber1 is not given, queue zero (0) is assumed. Beginning with Shorewall 4.6.10, a second queue number (queuenumber2) may be given. This specifies a range of queues to use. Packets are then balanced across the given queues. This is useful for multicore systems: start multiple instances of the userspace program on queues x, x+1, .. x+n and use "x:x+n". Packets belonging to the same connection are put into the same nfqueue. Beginning with Shorewall 5.1.0, queuenumber2 may be followed by the letter 'c' to indicate that the CPU ID will be used as an index to map packets to the queues. The idea is that you can improve performance if there's a queue per CPU. Requires the NFQUEUE CPU Fanout capability in your kernel and iptables. Beginning with Shorewall 4.6.10, the keyword bypass can be given. By default, if no userspace program is listening on an NFQUEUE, then all packets that are to be queued are dropped. When this option is used, the NFQUEUE rule behaves like ACCEPT instead.

CONTINUE

Pass the connection request past any other rules that it might also match (where the source or destination zone in those rules is a superset of the SOURCE or DEST in this policy). See shorewall-nesting[5](5) for additional information.

NONE

Assume that there will never be any packets from this SOURCE to this DEST. Shorewall will not create any infrastructure to handle such packets and you may not have any rules with this SOURCE and DEST in the /etc/shorewall/rules file. If such a packet is received, the result is undefined. NONE may not be used if the SOURCE or DEST columns contain the firewall zone ($FW) or "all".

LOGLEVEL (loglevel) - [log-level|ULOG|NFLOG]

Optional - if supplied, each connection handled under the default POLICY is logged at that level. If not supplied, no log message is generated. See syslog.conf(5) for a description of log levels. You may also specify ULOG or NFLOG (must be in upper case). This will log to the ULOG or NFLOG target and will send to a separate log through use of ulogd (http://www.netfilter.org/projects/ulogd/index.html).

For a description of logging, see shorewall-logging(5)[6].

If you don't want to log but need to specify the following column, place "-" here.

RATE (rate) - [-|limit]

where limit is one of: [-|[{s|d}[/vlsm]:[[name][(ht-buckets,ht-max)]:]]]rate/{sec|min|hour|day}[:burst]

[name1:]rate1/{sec|min|hour|day}[:burst1],[name2:]rate2/{sec|min|hour|day}[:burst2]

If passed, specifies the maximum TCP connection rate and the size of an acceptable burst. If not specified, TCP connections are not limited. If the burst parameter is omitted, a value of 5 is assumed. When s: or d: is specified, the rate applies per source IP address or per destination IP address respectively. The name may be chosen by the user and specifies a hash table to be used to count matching connections. If not give, the name shorewall is assumed. Where more than one POLICY or rule specifies the same name, the connections counts for the policies are aggregated and the individual rates apply to the aggregated count. Beginning with Shorewall 5.2.1, the s or d may be followed by a slash ("/") and an integer vlsm. When a vlsm is specified, all source or destination addresses encountered will be grouped according to the given prefix length and the so-created subnet will be subject to the rate limit.

Beginning with Shorewall 4.6.5, two limits may be specified, separated by a comma. In this case, the first limit (name1, rate1, burst1) specifies the per-source IP limit and the second limit specifies the per-destination IP limit.

Example: client:10/sec:20,:60/sec:100

Beginning with Shorewall 5.2.1, the table name, if any, may be followed by two integers separated by commas and enclosed in parentheses. The first integer (ht-buckets) specifies the number of buckets in the generated hash table. The second integer (ht-max) specifies the maximum number of entries in the hash table.

Example: s:client(1024,65536):10/sec

CONNLIMIT - limit[:mask]

May be used to limit the number of simultaneous connections from each individual host to limit connections. While the limit is only checked on connections to which this policy could apply, the number of current connections is calculated over all current connections from the SOURCE host. By default, the limit is applied to each host individually but can be made to apply to networks of hosts by specifying a mask. The mask specifies the width of a VLSM mask to be applied to the source address; the number of current connections is then taken over all hosts in the subnet source-address/mask.

## EXAMPLE
1.All connections from the local network to the internet are allowed

2.All connections from the internet are ignored but logged at syslog level KERNEL.INFO.

3.All other connection requests are rejected and logged at level KERNEL.INFO.

```
        #SOURCE         DEST            POLICY          LOG           BURST:LIMIT

        #                                               LEVEL

        loc             net             ACCEPT

        net             all             DROP            info

        #

        # THE FOLLOWING POLICY MUST BE LAST

        #

        all             all             REJECT          info
```

## FILES
/etc/shorewall/policy

/etc/shorewall6/policy

## SEE ALSO
https://shorewall.org/configuration_file_basics.htm#Pairs[7]

shorewall(8)

## NOTES
1.

shorewall-zones

https://shorewall.org/manpages/shorewall-zones.html

2.

shorewall-blrules

https://shorewall.org/manpages/shorewall-blrules.html

3.

shorewall-rules

https://shorewall.org/manpages/shorewall-rules.html

4.

shorewall.conf

https://shorewall.org/manpages/shorewall.conf.html

5.

shorewall-nesting

https://shorewall.org/manpages/shorewall-nesting.html

6.

shorewall-logging(5)

https://shorewall.org/shorewall_logging.html

7.

https://shorewall.org/configuration_file_basics.htm#Pairs

https://shorewall.org/configuration_file_basics.htm#Pairs


shorewall-providers

title: shorewall-providers(5)

summary: Shorewall Providers file

text:
# shorewall-providers(5)

## NAME
providers - Shorewall Providers file

## SYNOPSIS
/etc/shorewall/providers

## DESCRIPTION
This file is used to define additional routing tables. You will want to define an additional table if:

•You have connections to more than one ISP or multiple connections to the same ISP

•You run Squid as a transparent proxy on a host other than the firewall.

•You have other requirements for policy routing.

Each entry in the file defines a single routing table.

If you wish to omit a column entry but want to include an entry in the next column, use "-" for the omitted entry.

The columns in the file are as follows.

NAME - name

The provider name. Must be a valid shell variable name. The names 'local', 'main', 'default' and 'unspec' are reserved and may not be used as provider names.

NUMBER - number

The provider number -- a number between 1 and 15. Each provider must be assigned a unique value.

MARK (Optional) - value

A FWMARK value used in your shorewall-mangle(5)[1] file to direct packets to this provider. If PROVIDER_OFFSET is non-zero in shorewall.conf(5)[2], then the value must be a multiple of 2^^PROVIDER_OFFSET. In all cases, the number of significant bits may not exceed PROVIDER_OFFSET + PROVIDER_BITS.

DUPLICATE - routing-table-name

The name of an existing table to duplicate to create this routing table. May be main or the name of a previously listed provider. You may select only certain entries from the table to copy by using the COPY column below. This column should contain a dash ("-') when USE_DEFAULT_RT=Yes in shorewall.conf(5)[2].

INTERFACE - interface[:address]

The name of the network interface to the provider. Must be listed in shorewall-interfaces(5)[3]. In general, that interface should not have the proxyarp or proxyndp option specified unless loose is given in the OPTIONS column of this entry.

Important

For IPv6, if the interface is an Ethernet device and an IP address is supplied, it should be the upstream router's link-level address, not its global address.

Where more than one provider is serviced through a single interface, the interface must be followed by a colon and the IP address of the interface that is supplied by the associated provider.

GATEWAY - {-|address[,mac]|detect|none}

The IP address of the provider's gateway router. Beginning with Shorewall 4.6.2, you may also specify the MAC address of the gateway when there are multiple providers serviced through the same interface. When the MAC is not specified, Shorewall will detect the MAC during firewall start or restart. You can enter detect here and Shorewall will attempt to detect the gateway automatically.

Beginning with Shorewall 5.0.6, you may also enter none. This causes creation of a routing table with no default route in it.

For PPP devices, you may omit this column.

OPTIONS (Optional) - [-|option[,option]...]

A comma-separated list selected from the following. The order of the options is not significant but the list may contain no embedded white-space. autosrc

Added in Shorewall 4.5.17. Causes a host route to the provider's gateway router to be added to the provider's routing table. This is the default behavior unless overridden by a following noautosrc option.

track

If specified, inbound connections on this interface are to be tracked so that responses may be routed back out this same interface. You want to specify track if internet hosts will be connecting to local servers through this provider.

Beginning with Shorewall 4.4.3, track defaults to the setting of the TRACK_PROVIDERS option in shorewall.conf[2] (5). If you set TRACK_PROVIDERS=Yes and want to override that setting for an individual provider, then specify notrack (see below).

balance[=weight]

The providers that have balance specified will get outbound traffic load-balanced among them. By default, all interfaces with balance specified will have the same weight (1). You can change the weight of an interface by specifying balance=weight where weight is the weight of the route out of this interface. Prior to Shorewall 5.1.1, when USE_DEFAULT_RT=Yes, balance=1 is assumed unless the fallback, loose, load or tproxy option is specified. Beginning with Shorewall 5.1.1, when BALANCE_PROVIDERS=Yes, balance=1 is assumed unless the fallback, loose, load or tproxy option is specified.I

Caution

In IPV6, the balance option does not cause balanced default routes to be created; it rather causes a sequence of default routes with different metrics to be created.

loose

Shorewall normally adds a routing rule for each IP address on an interface which forces traffic whose source is that IP address to be sent using the routing table for that interface. Setting loose prevents creation of such rules on this interface.

load=probability

Added in Shorewall 4.6.0. This option provides an alternative method of load balancing based on probabilities. Providers to be balanced are given a probability (a number 0 > n >= 1) with up to 8 digits to the right of the decimal point. Beginning with Shorewall 4.6.10, a warning is issued if the sum of the probabilities is not 1.00000000.

noautosrc

Added in Shorewall 4.5.17. Prevents the addition of a host route to the provider's gateway router from being added to the provider's routing table. This option must be used with caution as it can cause start and restart failures.

notrack

Added in Shorewall 4.4.3. When specified, turns off track.

optional (deprecated for use with providers that do not share an interface)

If the interface named in the INTERFACE column is not up and configured with an IPv4 address then ignore this provider. If not specified, the value of the optional option for the INTERFACE in shorewall-interfaces(5)[3] is assumed. Use of that option is preferred to this one, unless an address is provider in the INTERFACE column.

primary

Added in Shorewall 4.6.6, primary is equivalent to balance=1 and is preferred when the remaining providers specify fallback or tproxy.

src=source-address

Specifies the source address to use when routing to this provider and none is known (the local client has bound to the 0 address). May not be specified when an address is given in the INTERFACE column. If this option is not used, Shorewall substitutes the primary IP address on the interface named in the INTERFACE column.

mtu=number

Specifies the MTU when forwarding through this provider. If not given, the MTU of the interface named in the INTERFACE column is assumed.

fallback[=weight]

Indicates that a default route through the provider should be added to the default routing table (table 253). If a weight is given, a balanced route is added with the weight of this provider equal to the specified weight. If the option is given without a weight, a separate default route is added through the provider's gateway; the route has a metric equal to the provider's NUMBER. Prior to Shorewall 4.4.24, the option is ignored with a warning message if USE_DEFAULT_RT=Yes in shorewall.conf.

Caution

In IPV6, specifying the fallback option on multiple providers does not cause balanced fallback routes to be created; it rather causes a sequence of fallback routes with different metrics to be created.

tproxy

Added in Shorewall 4.5.4. Used for supporting the TPROXY action in shorewall-mangle(5). See https://shorewall.org/Shorewall_Squid_Usage.html[4]. When specified, the MARK, DUPLICATE and GATEWAY columns should be empty, INTERFACE should be set to 'lo' and tproxy should be the only OPTION. Only one tproxy provider is allowed.

hostroute

Added in Shorewall 4.5.21. This is the default behavior that results in a host route to the defined GATEWAY being inserted into the main routing table and into the provider's routing table. hostroute is required for older distributions but nohostroute (below) is appropriate for recent distributions. hostroute may interfere with Zebra's ability to add routes on some distributions such as Debian 7. This option defaults to on when BALANCE_PROVIDERS=Yes, in shorewall.conf(5)[2].

nohostroute

Added in Shorewall 4.5.21. nohostroute inhibits addition of a host route to the defined GATEWAY being inserted into the main routing table and into the provider's routing table. nohostroute is not appropriate for older distributions but is appropriate for recent distributions. nohostroute allows Zebra's to correctly add routes on some distributions such as Debian 7. This option defaults to off when BALANCE_PROVIDERS=Yes, in shorewall.conf(5)[2].

persistent

Added in Shorewall 5.0.2 and alters the behavior of the disable command:

•The provider's routing table still contains the apprioriate default route.

•Unless the noautosrc option is specified, routing rules are generated to route traffic from the interfaces address(es) out of the provider's routing table.

•Persistent routing rules in shorewall-rtrules(5)[5] are present.

Note

The generated script will attempt to reenable a disabled persistent provider during execution of the start, restart and reload commands. When persistent is not specified, only the enable and reenable commands can reenable the provider.

Important

RESTORE_DEFAULT_ROUTE=Yes in shorewall[6].conf is not recommended when the persistent option is used, as restoring default routes to the main routing table can prevent link status monitors such as foolsm from correctly detecting non-working providers.

COPY - [{none|interface[,interface]...}]

A comma-separated list of other interfaces on your firewall. Wildcards specified using an asterisk ("*") are permitted (e.g., tun* ). Usually used only when DUPLICATE is main. Only copy routes through INTERFACE and through interfaces listed here. If you only wish to copy routes through INTERFACE, enter none in this column. Beginning with Shorewall 4.5.17, blackhole, unreachable and prohibit routes are no longer copied by default but may be copied by including blackhole,unreachable and prohibit respectively in the COPY list.

## EXAMPLES
IPv4 Example 1:

You run squid in your DMZ on IP address 192.168.2.99. Your DMZ interface is eth2

```
        #NAME   NUMBER  MARK DUPLICATE  INTERFACE GATEWAY       OPTIONS

        Squid   1       1    -          eth2      192.168.2.99  -
```

IPv4 Example 2:

eth0 connects to ISP 1. The IP address of eth0 is 206.124.146.176 and the ISP's gateway router has IP address 206.124.146.254. eth1 connects to ISP 2. The IP address of eth1 is 130.252.99.27 and the ISP's gateway router has IP address 130.252.99.254.

eth2 connects to a local network.

```
        #NAME NUMBER MARK DUPLICATE INTERFACE GATEWAY          OPTIONS            COPY

        ISP1  1       1    main      eth0      206.124.146.254 track,balance      eth2

        ISP2  2       2    main      eth1      130.252.99.254  track,balance      eth2
```

IPv6 Example 1:

You run squid in your DMZ on IP address 2002:ce7c:92b4:1::2. Your DMZ interface is eth2

```
        #NAME   NUMBER  MARK DUPLICATE  INTERFACE GATEWAY              OPTIONS

        Squid   1       1    -          eth2      2002:ce7c:92b4:1::2  -
```

IPv6 Example 2:

eth0 connects to ISP 1. The ISP's gateway router has IP address 2001:ce7c:92b4:1::2. eth1 connects to ISP 2. The ISP's gateway router has IP address 2001:d64c:83c9:12::8b.

eth2 connects to a local network.

```
        #NAME NUMBER MARK DUPLICATE INTERFACE GATEWAY               OPTIONS    COPY

        ISP1  1       1    main      eth0     2001:ce7c:92b4:1::2   track      eth2

        ISP2  2       2    main      eth1     2001:d64c:83c9:12::8b track      eth2
```

## FILES
/etc/shorewall/providers

/etc/shorewall6/providers

## SEE ALSO
https://shorewall.org/MultiISP.html[6]

https://shorewall.org/configuration_file_basics.htm#Pairs[7]

shorewall(8)

## NOTES
1.

shorewall-mangle(5)

https://shorewall.org/manpages/shorewall-mangle.html

2.

shorewall.conf(5)

https://shorewall.org/manpages/shorewall.conf.html

3.

shorewall-interfaces(5)

https://shorewall.org/manpages/shorewall-interfaces.html

4.

https://shorewall.org/Shorewall_Squid_Usage.html

https://shorewall.org/Shorewall_Squid_Usage.html

5.

shorewall-rtrules(5)

https://shorewall.org/manpages/shorewall-rtrules.html

6.

https://shorewall.org/MultiISP.html

https://shorewall.org/MultiISP.html

7.

https://shorewall.org/configuration_file_basics.htm#Pairs

https://shorewall.org/configuration_file_basics.htm#Pairs


shorewall-proxyarp

title: shorewall-proxyarp(5)

summary: Shorewall Proxy ARP file

text:
# shorewall-proxyarp(5)

## NAME
proxyarp - Shorewall Proxy ARP file

## SYNOPSIS
/etc/shorewall/proxyarp

## DESCRIPTION
IPv4 only.

This file is used to define Proxy ARP. There is one entry in this file for each IP address to be proxied.

The columns in the file are as follows.

ADDRESS - address

IP Address.

INTERFACE - interface (Optional as of Shorewall 4.4.16)

Local interface where system with the ip address in ADDRESS is connected. This column is only required when HAVEROUTE is set to No (no) or is left empty.

EXTERNAL - interface

External Interface to be used to access this system from the Internet.

HAVEROUTE - [-|Yes|No]

If there is already a route from the firewall to the host whose address is given, enter Yes or yes in this column. Otherwise, enter no or No or leave the column empty and Shorewall will add the route for you. If Shorewall adds the route, its persistence depends on the value of thePERSISTENT column contains Yes; otherwise, shorewall stop or shorewall clear will delete the route.

PERSISTENT - [-|Yes|No]

If HAVEROUTE is No or no, then the value of this column determines if the route added by Shorewall persists after a shorewall stop or a shorewall clear. If this column contains Yes or yes then the route persists; If the column is empty or contains No or no then the route is deleted by shorewall stop or shorewall clear.

## EXAMPLE
Example 1:

Host with IP 155.186.235.6 is connected to interface eth1 and we want hosts attached via eth0 to be able to access it using that address.

```
       #ADDRESS        INTERFACE       EXTERNAL

       155.186.235.6   eth1            eth0
```

## FILES
/etc/shorewall/proxyarp

## SEE ALSO
https://shorewall.org/ProxyARP.htm[1]

https://shorewall.org/configuration_file_basics.htm#Pairs[2]

shorewall(8)

## NOTES
1.

https://shorewall.org/ProxyARP.htm

https://shorewall.org/ProxyARP.htm

2.

https://shorewall.org/configuration_file_basics.htm#Pairs

https://shorewall.org/configuration_file_basics.htm#Pairs


shorewall-proxyndp

title: shorewall-proxyndp(5)

summary: Shorewall6 Proxy NDP file

text:
# shorewall-proxyndp(5)

## NAME
proxyndp - Shorewall6 Proxy NDP file

## SYNOPSIS
/etc/shorewall6/proxyndp

## DESCRIPTION
This file was added in Shorewall 4.4.16 and is used to define Proxy NDP. There is one entry in this file for each IPv6 address to be proxied.

The columns in the file are as follows.

ADDRESS - address

IPv6 Address.

INTERFACE - interface (Optional)

Local interface where system with the ip address in ADDRESS is connected. Only required when the HAVEROUTE column is left empty or is set to no or No.

EXTERNAL - interface

External Interface to be used to access this system from the Internet.

HAVEROUTE - [-|Yes|No]

If there is already a route from the firewall to the host whose address is given, enter Yes or yes in this column. Otherwise, enter no or No or leave the column empty and Shorewall will add the route for you. If Shorewall6 adds the route, its persistence depends on the value of thePERSISTENT column contains Yes; otherwise, shorewall6 stop or shorewall clear6 will delete the route.

PERSISTENT - [-|Yes|No]

If HAVEROUTE is No or no, then the value of this column determines if the route added by Shorewall persists after a shorewall6 stop or a shorewall6 clear. If this column contains Yes or yes then the route persists; If the column is empty or contains No or no then the route is deleted by shorewall6 stop or shorewall6 clear.

## EXAMPLE
Example 1:

Host with IPv6 2001:470:b:227::44 is connected to interface eth1 and we want hosts attached via eth0 to be able to access it using that address.

```
       #ADDRESS             INTERFACE       EXTERNAL

       2001:470:b:227::44   eth1            eth0
```

## FILES
/etc/shorewall6/proxyndp

## SEE ALSO
https://shorewall.org/configuration_file_basics.htm#Pairs[1]

shorewall6(8), shorewall6-accounting(5), shorewall6-actions(5), shorewall6-blacklist(5), shorewall6-exclusion(5), shorewall6-hosts(5), shorewall6-interfaces(5), shorewall6-maclist(5), shorewall6-nesting(5), shorewall6-netmap(5),shorewall6-params(5), shorewall6-policy(5), shorewall6-providers(5), shorewall6-rtrules(5), shorewall6-routestopped(5), shorewall6-rules(5), shorewall6.conf(5), shorewall6-secmarks(5), shorewall6-tcclasses(5), shorewall6-tcdevices(5), shorewall6-mangle(5), shorewall6-tos(5), shorewall6-tunnels(5), shorewall6-zones(5)

## NOTES
1.

https://shorewall.org/configuration_file_basics.htm#Pairs

https://shorewall.org/configuration_file_basics.htm#Pairs


shorewall-routes

title: shorewall-routes(5)

summary: Shorewall file

text:
# shorewall-routes(5)

## NAME
routes - Shorewall file

## SYNOPSIS
/etc/shorewall[6]/routes

## DESCRIPTION
This file was added in Shorewall 4.4.15 and is used to define routes to be added to provider routing tables.

The columns in the file are as follows.

PROVIDER

The name or number of a provider defined in shorewall-providers[1] (5). Beginning with Shorewall 4.5.14, you may also enter main in this column to add routes to the main routing table.

DEST

Destination host address or network address.

GATEWAY (Optional)

If specified, gives the IP address of the gateway to the DEST. Beginning with Shorewall 4.5.14, you may specify blackhole in this column to create a blackhole route.

Beginning with Shorewall 4.5.15, you may specify prohibit or unreachable in this column to create a prohibit or unreachable route respectively.

DEVICE (Optional)

Specifies the device route. If neither DEVICE nor GATEWAY is given, then the INTERFACE specified for the PROVIDER in shorewall-providers[1] (5). This column must be omitted if blackhole, prohibit or unreachable is specified in the GATEWAY column.

OPTIONS (Optional)

Added in Shorewall 5.0.2. Allowed options are:

persistent

If specified, the route remains in the provider's routing table even when the provider is disabled.

## FILES
/etc/shorewall/routes

/etc/shorewall6/routes

## SEE ALSO
https://shorewall.org/configuration_file_basics.htm#Pairs[2]

shorewall(8)

## NOTES
1.

shorewall-providers

https://shorewall.org/manpages/shorewall-providers.html

2.

https://shorewall.org/configuration_file_basics.htm#Pairs

https://shorewall.org/configuration_file_basics.htm#Pairs


shorewall-rtrules

title: shorewall-rtrules(5)

summary: Shorewall Routing Rules file

text:
# shorewall-rtrules(5)

## NAME
rtrules - Shorewall Routing Rules file

## SYNOPSIS
/etc/shorewall[6]/rtrules

## DESCRIPTION
Entries in this file cause traffic to be routed to one of the providers listed in shorewall-providers[1](5).

The columns in the file are as follows.

SOURCE (Optional) - {-|[&]interface|address|interface:address}

An ip address (network or host) that matches the source IP address in a packet. May also be specified as an interface name optionally followed by ":" and an address. If the device lo is specified, the packet must originate from the firewall itself. Beginning with Shorewall 4.5.0, you may specify &interface in this column to indicate that the source is the primary IP address of the named interface.

Beginning with Shorewall 4.6.8, you may specify a comma-separated list of addresses in this column.

DEST (Optional) - {-|address}

An ip address (network or host) that matches the destination IP address in a packet. If you choose to omit either SOURCE or DEST, place "-" in that column. Note that you may not omit both SOURCE and DEST.

Beginning with Shorewall 4.6.8, you may specify a comma-separated list of addresses in this column.

PROVIDER - {provider-name|provider-number|main}

The provider to route the traffic through. May be expressed either as the provider name or the provider number. May also be main or 254 for the main routing table. This can be used in combination with VPN tunnels, see example 2 below.

PRIORITY - priority[!]

The rule's numeric priority which determines the order in which the rules are processed. Rules with equal priority are applied in the order in which they appear in the file. 1000-1999

Before Shorewall-generated 'MARK' rules

11000-11999

After 'MARK' rules but before Shorewall-generated rules for ISP interfaces.

26000-26999

After ISP interface rules but before 'default' rule.

Beginning with Shorewall 5.0.2, the priority may be followed optionally by an exclaimation mark ("!"). This causes the rule to remain in place if the interface is disabled.

Caution

Be careful when using rules of the same PRIORITY as some unexpected behavior can occur when multiple rules have the same SOURCE. For example, in the following rules, the second rule overwrites the first unless the priority in the second is changed to 19001 or higher:

```
10.10.0.0/24    192.168.5.6 provider1 19000
10.10.0.0/24    -           provider2 19000
```

MARK - {-|mark[/mask]}

Optional -- added in Shorewall 4.4.25. For this rule to be applied to a packet, the packet's mark value must match the mark when logically anded with the mask. If a mask is not supplied, Shorewall supplies a suitable provider mask.

## EXAMPLES
Example 1:

You want all traffic coming in on eth1 to be routed to the ISP1 provider.

```
        #SOURCE                 DEST            PROVIDER        PRIORITY      MASK

        eth1                    -               ISP1            1000
```

IPv4 Example 2:

You use OpenVPN (routed setup /tunX) in combination with multiple providers. In this case you have to set up a rule to ensure that the OpenVPN traffic is routed back through the tunX interface(s) rather than through any of the providers. 10.8.0.0/24 is the subnet chosen in your OpenVPN configuration (server 10.8.0.0 255.255.255.0).

```
         #SOURCE                 DEST            PROVIDER        PRIORITY     MASK

         -                       10.8.0.0/24     main            1000
```

## FILES
/etc/shorewall/rtrules

/etc/shorewall6/rtrules

## SEE ALSO
https://shorewall.org/MultiISP.html[2]

https://shorewall.org/configuration_file_basics.htm#Pairs[3]

shorewall(8)

## NOTES
1.

shorewall-providers

https://shorewall.org/manpages/shorewall-providers.html

2.

https://shorewall.org/MultiISP.html

https://shorewall.org/MultiISP.html

3.

https://shorewall.org/configuration_file_basics.htm#Pairs

https://shorewall.org/configuration_file_basics.htm#Pairs


shorewall-rules

title: shorewall-rules(5)

summary: Shorewall rules file

text:
# shorewall-rules(5)

## NAME
rules - Shorewall rules file

## SYNOPSIS
/etc/shorewall[6]/rules

## DESCRIPTION
Entries in this file govern connection establishment by defining exceptions to the policies laid out in shorewall-policy[1](5). By default, subsequent requests and responses are automatically allowed using connection tracking. For any particular (source,dest) pair of zones, the rules are evaluated in the order in which they appear in this file and the first terminating match is the one that determines the disposition of the request. All rules are terminating except LOG and COUNT rules.

Warning

If you masquerade or use SNAT from a local system to the internet, you cannot use an ACCEPT rule to allow traffic from the internet to that system. You must use a DNAT rule instead.

The rules file is divided into sections. Each section is introduced by a "Section Header" which is a line beginning with ?SECTION and followed by the section name.

Sections are as follows and must appear in the order listed:

ALL

This section was added in Shorewall 4.4.23. Rules in this section are applied, regardless of the connection tracking state of the packet and are applied before rules in the other sections.

ESTABLISHED

Packets in the ESTABLISHED state are processed by rules in this section. The only ACTIONs allowed in this section are ACCEPT, DROP, REJECT, LOG, NFLOG, NFQUEUE and QUEUE

There is an implicit ACCEPT rule inserted at the end of this section.

RELATED

Packets in the RELATED state are processed by rules in this section. The only ACTIONs allowed in this section are ACCEPT, DROP, REJECT, LOG, NFLOG, NFQUEUE and QUEUE

There is an implicit rule added at the end of this section that invokes the RELATED_DISPOSITION (shorewall.conf[2](5)).

INVALID

Added in Shorewall 4.5.13. Packets in the INVALID state are processed by rules in this section. The only Actions allowed in this section are ACCEPT, DROP, REJECT, LOG, NFLOG, NFQUEUE and QUEUE.

There is an implicit rule added at the end of this section that invokes the INVALID_DISPOSITION (shorewall.conf[2](5)).

UNTRACKED

Added in Shorewall 4.5.13. Packets in the UNTRACKED state are processed by rules in this section. The only Actions allowed in this section are ACCEPT, DROP, REJECT, LOG, NFLOG, NFQUEUE and QUEUE.

There is an implicit rule added at the end of this section that invokes the UNTRACKED_DISPOSITION (shorewall.conf[2](5)).

NEW

Packets in the NEW state are processed by rules in this section. If the INVALID and/or UNTRACKED sections are empty or not included, then the packets in the corresponding state(s) are also processed in this section.

Note

If you are not familiar with Netfilter to the point where you are comfortable with the differences between the various connection tracking states, then it is suggested that you place all of your rules in the NEW section (That's after the line that reads ?SECTION NEW').

Warning

If you specify FASTACCEPT=Yes in shorewall.conf[2](5) then the ALL, ESTABLISHED and RELATED sections must be empty.

An exception is made if you are running Shorewall 4.4.27 or later and you have specified a non-default value for RELATED_DISPOSITION or RELATED_LOG_LEVEL. In that case, you may have rules in the RELATED section of this file.

You may omit any section that you don't need. If no Section Headers appear in the file then all rules are assumed to be in the NEW section.

When defining rules that rewrite the destination IP address and/or port number (namely DNAT and REDIRECT rules), it is important to keep straight which columns in the file specify the packet before rewriting and which specify how the packet will look after rewriting.

•The DEST column specifies the final destination for the packet after rewriting and can include the final IP address and/or port number.

•The remaining columns specify characteristics of the packet before rewriting. In particular, the ORIGDEST column gives the original destination IP address of the packet and the DPORT column give the original destination port(s).

The columns in the file are as follows (where the column name is followed by a different name in parentheses, the different name is used in the alternate specification syntax).

ACTION - target[:{log-level|none}[!][:tag]]

Specifies the action to be taken if the connection request matches the rule. target must be one of the following. ACCEPT

Allow the connection request.

ACCEPT+

like ACCEPT but also excludes the connection from any subsequent matching DNAT[-] or REDIRECT[-] rules. Use with IPv6 requires Shorewall 4.5.14 or later.

ACCEPT!

like ACCEPT but exempts the rule from being suppressed by OPTIMIZE=1 in shorewall.conf[2](5).

action

The name of an action declared in shorewall-actions[3](5) or in /usr/share/shorewall[6]/actions.std.

ADD(ipset:flags[:timeout])

Added in Shorewall 4.4.12. Causes addresses and/or port numbers to be added to the named ipset. The flags specify the address or tuple to be added to the set and must match the type of ipset involved. For example, for an iphash ipset, either the SOURCE or DESTINATION address can be added using flags src or dst respectively (see the -A command in ipset (8)). Beginning with Shorewall 5.0.3, an optional timeout can be specified. This is the number of seconds that the new entry in the ipset is to remain valid and overrides any timeout specified when the ipset was created.

ADD is non-terminating. Even if a packet matches the rule, it is passed on to the next rule.

AUDIT[(accept|drop|reject)]

Added in Shorewall 4.5.10. Audits the packet with the specified type; if the type is omitted, then drop is assumed. Require AUDIT_TARGET support in the kernel and iptables.

A_ACCEPT, A_ACCEPT+ and A_ACCEPT!

Added in Shorewall 4.4.20. Audited versions of ACCEPT, ACCEPT+ and ACCEPT! respectively. Require AUDIT_TARGET support in the kernel and iptables. A_ACCEPT+ with IPv6 requires Shorewall 4.5.14 or later.

A_DROP and A_DROP!

Added in Shorewall 4.4.20. Audited versions of DROP and DROP! respectively. Require AUDIT_TARGET support in the kernel and iptables.

A_REJECT AND A_REJECT!

Added in Shorewall 4.4.20. Audited versions of REJECT and REJECT! respectively. Require AUDIT_TARGET support in the kernel and iptables.

?COMMENT

the rest of the line will be attached as a comment to the Netfilter rule(s) generated by the following entries. The comment will appear delimited by "/* ... */" in the output of "shorewall show <chain>". To stop the comment from being attached to further rules, simply include ?COMMENT on a line by itself.

CONMARK({mark})

Added in Shorewall 5.0.7, CONNMARK is identical to MARK with the exception that the mark is assigned to connection to which the packet belongs is marked rather than to the packet itself.

CONTINUE

For experts only. Do not process any of the following rules for this (source zone,destination zone). If the source and/or destination IP address falls into a zone defined later in shorewall-zones[4](5) or in a parent zone of the source or destination zones, then this connection request will be passed to the rules defined for that (those) zone(s). See shorewall-nesting[5](5) for additional information.

CONTINUE!

like CONTINUE but exempts the rule from being suppressed by OPTIMIZE=1 in shorewall.conf[2](5).

COUNT

Simply increment the rule's packet and byte count and pass the packet to the next rule.

DEL(ipset:flags)

Added in Shorewall 4.4.12. Causes an entry to be deleted from the named ipset. The flags specify the address or tuple to be deleted from the set and must match the type of ipset involved. For example, for an iphash ipset, either the SOURCE or DESTINATION address can be deleted using flags src or dst respectively (see the -D command in ipset (8)). DEL is non-terminating. Even if a packet matches the rule, it is passed on to the next rule.

DNAT

Forward the request to another system (and optionally another port). Use with IPv6 requires Shorewall 4.5.14 or later.

DNAT-

Advanced users only. Like DNAT but only generates the DNAT iptables rule and not the companion ACCEPT rule. Use with IPv6 requires Shorewall 4.5.14 or later.

DROP

Ignore the request.

DROP!

like DROP but exempts the rule from being suppressed by OPTIMIZE=1 in shorewall.conf[2](5).

HELPER

Added in Shorewall 4.5.7. This action requires that the HELPER column contains the name of the Netfilter helper to be associated with connections matching this connection. May only be specified in the NEW section and is useful for being able to specify a helper when the applicable policy is ACCEPT. No destination zone should be specified in HELPER rules.

INLINE[(action)]

Added in Shorewall 4.5.16. This action allows you to construct most of the rule yourself using iptables syntax. The part that you specify must follow two semicolons (';;') and is completely free-form. If the target of the rule (the part following 'j') is something that Shorewall supports in the ACTION column, then you may enclose it in parentheses (e.g., INLINE(ACCEPT)). Otherwise, you can include it after the semicolon(s). In this case, you must declare the target as a builtin action in shorewall-actions[3](5). Some considerations when using INLINE:

•The p, s, d, i, o, policy, and state match (state or conntrack --ctstate) matches will always appear in the front of the rule in that order.

•When multiple matches are specified, the compiler will keep them in the order in which they appear (excluding the above listed ones), but they will not necessarily be at the end of the generated rule. For example, if addresses are specified in the SOURCE and/or DEST columns, their generated matches will appear after those specified using ';;' or ';'.

IPTABLES({iptables-target [option ...])

IPv4 only. This action allows you to specify an iptables target with options (e.g., 'IPTABLES(MARK --set-xmark 0x01/0xff)'. If the iptables-target is not one recognized by Shorewall, the following error message will be issued:

```
    ERROR: Unknown target (iptables-target)
```

This error message may be eliminated by adding the iptables-target as a builtin action in shorewall-actions[3](5).

Important

If you specify REJECT as the iptables-target, the target of the rule will be the iptables REJECT target and not Shorewall's builtin 'reject' chain which is used when REJECT (see below) is specified as the target in the ACTION column.

IP6TABLES({ip6tables-target [option ...])

IPv6 only. This action allows you to specify an ip6tables target with options (e.g., 'IPTABLES(MARK --set-xmark 0x01/0xff)'. If the ip6tables-target is not one recognized by Shorewall, the following error message will be issued:

```
    ERROR: Unknown target (ip6tables-target)
```

This error message may be eliminated by adding the ip6tables-target as a builtin action in shorewall-actions[3](5).

Important

If you specify REJECT as the ip6tables-target, the target of the rule will be the i6ptables REJECT target and not Shorewall's builtin 'reject' chain which is used when REJECT (see below) is specified as the target in the ACTION column.

LOG:level

Simply log the packet and continue with the next rule.

macro[(macrotarget)]

The name of a macro defined in a file named macro.macro. If the macro accepts an action parameter (Look at the macro source to see if it has PARAM in the TARGET column) then the macro name is followed by the parenthesized macrotarget (ACCEPT, DROP, REJECT, ...) to be substituted for the parameter. Example: FTP(ACCEPT).

The older syntax where the macro name and the target are separated by a slash (e.g. FTP/ACCEPT) is still allowed but is deprecated.

MARK({mark})

where mark is a packet mark value. Added in Shorewall 5.0.7, MARK requires "Mark in filter table" support in your kernel and iptables.

Normally will set the mark value of the current packet. If preceded by a vertical bar ("|"), the mark value will be logically ORed with the current mark value to produce a new mark value. If preceded by an ampersand ("&"), will be logically ANDed with the current mark value to produce a new mark value.

Both "|" and "&" require Extended MARK Target support in your kernel and iptables.

The mark value may be optionally followed by "/" and a mask value (used to determine those bits of the connection mark to actually be set). When a mask is specified, the result of logically ANDing the mark value with the mask must be the same as the mark value.

NFLOG[(nflog-parameters)]

Added in Shorewall 4.5.9.3. Queues matching packets to a back end logging daemon via a netlink socket then continues to the next rule. See https://shorewall.org/shorewall_logging.html[6]. The nflog-parameters are a comma-separated list of up to 3 numbers:

•The first number specifies the netlink group (0-65535). If omitted (e.g., NFLOG(,0,10)) then a value of 0 is assumed.

•The second number specifies the maximum number of bytes to copy. If omitted, 0 (no limit) is assumed.

•The third number specifies the number of log messages that should be buffered in the kernel before they are sent to user space. The default is 1.

NFLOG is similar to LOG:NFLOG[(nflog-parameters)], except that the log level is not changed when this ACTION is used in an action or macro body and the invocation of that action or macro specifies a log level.

NFQUEUE[([queuenumber1[:queuenumber2[c]][,bypass]]|bypass)]

Queues the packet to a user-space application using the nfnetlink_queue mechanism. If a queuenumber1 is not specified, queue zero (0) is assumed. Beginning with Shorewall 4.6.10, the keyword bypass can be given. By default, if no userspace program is listening on an NFQUEUE, then all packets that are to be queued are dropped. When this option is used, the NFQUEUE rule behaves like ACCEPT instead. Also beginning in Shorewall 4.6.10, a second queue number (queuenumber2) may be specified. This specifies a range of queues to use. Packets are then balanced across the given queues. This is useful for multicore systems: start multiple instances of the userspace program on queues x, x+1, .. x+n and use "x:x+n". Packets belonging to the same connection are put into the same nfqueue. Beginning with Shorewall 5.1.0, queuenumber2 may be followed by the letter 'c' to indicate that the CPU ID will be used as an index to map packets to the queues. The idea is that you can improve performance if there's a queue per CPU. Requires the NFQUEUE CPU Fanout capability in your kernel and iptables.

NFQUEUE![([queuenumber1[:queuenumber2[c]][,bypass]]|bypass)]

like NFQUEUE but exempts the rule from being suppressed by OPTIMIZE=1 in shorewall.conf[2](5).

NONAT

Excludes the connection from any subsequent DNAT[-] or REDIRECT[-] rules but doesn't generate a rule to accept the traffic. Use with IPv6 requires Shorewall 4.5.14 or later.

QUEUE

Queue the packet to a user-space application such as ftwall (http://p2pwall.sf.net). The application may reinsert the packet for further processing.

QUEUE!

like QUEUE but exempts the rule from being suppressed by OPTIMIZE=1 in shorewall.conf[2](5).

REJECT[(option)]

disallow the request and return an icmp-unreachable or an RST packet. If no option is passed, Shorewall selects the appropriate option based on the protocol of the packet. Beginning with Shorewall 5.0.8, the type of reject may be specified in the option paramater. Valid IPv4 option values are:

icmp-net-unreachable

icmp-host-unreachable

icmp-port-unreachable

icmp-proto-unreachable

icmp-net-prohibited

icmp-host-prohibited

icmp-admin-prohibited

icmp-tcp-reset (the PROTO column

must specify TCP). Beginning with Shorewall 5.1.3, this

option may also be specified as

tcp-reset.

Valid IPv6 option values are: icmp6-no-route

no-route

icmp6-adm-prohibited

adm-prohibited

icmp6-addr-unreachable

addr-unreach

icmp6-port-unreachable

tcp-reset (the PROTO column must

specify TCP)

REJECT!

like REJECT but exempts the rule from being suppressed by OPTIMIZE=1 in shorewall.conf[2](5).

REDIRECT

Redirect the request to a server running on the firewall. Use with IPv6 requires Shorewall 4.5.14 or later.

REDIRECT-

Advanced users only. Like REDIRECT but only generates the REDIRECT iptables rule and not the companion ACCEPT rule. Use with IPv6 requires Shorewall 4.5.14 or later.

TARPIT [(tarpit | honeypot | reset)]

Added in Shorewall 4.6.6. TARPIT captures and holds incoming TCP connections using no local per-connection resources.

TARPIT only works with the PROTO column set to tcp (6), and is totally application agnostic. This module will answer a TCP request and play along like a listening server, but aside from sending an ACK or RST, no data is sent. Incoming packets are ignored and dropped. The attacker will terminate the session eventually. This module allows the initial packets of an attack to be captured by other software for inspection. In most cases this is sufficient to determine the nature of the attack.

This offers similar functionality to LaBrea <http://www.hackbusters.net/LaBrea/> but does not require dedicated hardware or IPs. Any TCP port that you would normally DROP or REJECT can instead become a tarpit.

The target accepts a single optional parameter:

tarpit

This mode is the default and completes a connection with the attacker but limits the window size to 0, thus keeping the attacker waiting long periods of time. While he is maintaining state of the connection and trying to continue every 60-240 seconds, we keep none, so it is very lightweight. Attempts to close the connection are ignored, forcing the remote side to time out the connection in 12-24 minutes.

honeypot

This mode completes a connection with the attacker, but signals a normal window size, so that the remote side will attempt to send data, often with some very nasty exploit attempts. We can capture these packets for decoding and further analysis. The module does not send any data, so if the remote expects an application level response, the game is up.

reset

This mode is handy because we can send an inline RST (reset). It has no other function.

ULOG[(ulog-parameters)]

IPv4 only. Added in Shorewall 4.5.10. Queues matching packets to a back end logging daemon via a netlink socket then continues to the next rule. See shorewall-logging(5)[7]. Similar to LOG:ULOG[(ulog-parameters)], except that the log level is not changed when this ACTION is used in an action or macro body and the invocation of that action or macro specifies a log level.

The target may optionally be followed by ":" and a syslog log level (e.g, REJECT:info or Web(ACCEPT):debug). This causes the packet to be logged at the specified level. Note that if the ACTION involves destination network address translation (DNAT, REDIRECT, etc.) then the packet is logged before the destination address is rewritten.

If the ACTION names an action declared in shorewall-actions[3](5) or in /usr/share/shorewall/actions.std then:

•If the log level is followed by "!' then all rules in the action are logged at the log level.

•If the log level is not followed by "!" then only those rules in the action that do not specify logging are logged at the specified level.

•The special log level none! suppresses logging by the action.

You may also specify ULOG (IPv4 only) or NFLOG (must be in upper case) as a log level.This will log to the ULOG or NFLOG target for routing to a separate log through use of ulogd (shorewall-logging(5)[7]).

Actions specifying logging may be followed by a log tag (a string of alphanumeric characters) which is appended to the string generated by the LOGPREFIX (in shorewall.conf[2](5)).

Example: ACCEPT:info:ftp would include 'ftp ' at the end of the log prefix generated by the LOGPREFIX setting.

SOURCE - source-spec[,...]

Source hosts to which the rule applies. source-spec is one of the following:

zone[,...[+]]

The name of a zone defined in shorewall-zones[4](5). When only the zone name is specified, the packet source may be any host in that zone. zone may also be one of the following:

all[+]

all, without the "-" means "All Zones, including the firewall zone". Normally all omits intra-zone traffic, but intra-zone traffic can be included specifying "+".

any[+]

any is equivalent to all when there are no nested zones. When there are nested zones, any only refers to top-level zones (those with no parent zones). Note that any excludes all vserver zones, since those zones are nested within the firewall zone.

none

When none is used either in the SOURCE or DEST column, the rule is ignored.

Similar to with all and any, intra-zone traffic is normally excluded when multiple zones are listed. Intra-zone traffic may be included by following the list with a plus sign ("+").

all and any may be followed by an exclamation point ("!") and a comma-separated list of zone names to be omitted.

zone:[!]interface

When this form is used, interface must be the name of an interface associated with the named zone in either shorewall-interfaces[8](5) or shorewall-hosts[9](5). Only packets from hosts in the zone that arrive through the named interface will match the rule. Beginning with Shorweall 5.2.1, the interface may be preceded with '!' which matches all interfaces associated with the zone except the one specified.

zone:address[,...]

where address can be:

•A host or network IP address. A network address may be followed by exclusion (see shorewall-exclusion[10](5)).

•An address range, specified using the syntax lowaddress-highaddress.

•+ipset where ipset is the name of an ipset and must be preceded by a plus sign ("+").

•A MAC address in Shorewall format (preceded by a tilde ("~") and with the hex byte values separated by dashes (e.g., "~00-0a-f6-04-9c-7d").

•^country-code where country-code is a two-character ISO-3661 country code preceded by a caret ("^").

•^country-code-list where country-code-list is a comma-separated list of up to 15 ISO-3661 country codes enclosed in square brackets ("[...]").

•The primary IP address of a firewall interface can be specified by an ampersand ('&') followed by the logical name of the interface as found in the INTERFACE column of shorewall-interfaces[8] (5).

zone:interface:address[,...]

This form combines the preceding two and requires that both the incoming interface and source address match.

zone:exclusion

This form matches if the host IP address does not match any of the entries in the exclusion (see shorewall-exclusion[10](5)).

zone:interface:exclusion

This form matches packets from the named zone entering through the specified interface where the source address does not match any entry in the exclusion.

Beginning with Shorewall 5.1.0, multiple source-specs may be listed, provided that extended forms of the source-spec are used: zone:(interface)

zone:(address[,...])

zone:(interface:address[,...])

zone:(exclusion)

zone:(interface:exclusion) Examples:

dmz:192.168.2.2

Host 192.168.2.2 in the DMZ

net:155.186.235.0/24

Subnet 155.186.235.0/24 on the Internet

loc:192.168.1.1,192.168.1.2

Hosts 192.168.1.1 and 192.168.1.2 in the local zone.

loc:~00-A0-C9-15-39-78

Host in the local zone with MAC address 00:A0:C9:15:39:78.

net:192.0.2.11-192.0.2.17

Hosts 192.0.2.11-192.0.2.17 in the net zone.

net:!192.0.2.11-192.0.2.17

All hosts in the net zone except for 192.0.2.11-192.0.2.17.

net:155.186.235.0/24!155.186.235.16/28

Subnet 155.186.235.0/24 on the Internet except for 155.186.235.16/28

$FW:&eth0

The primary IP address of eth0 in the firewall zone.

loc,dmz

Both the loc and dmz zones.

all!dmz

All but the dmz zone.

all+!$FW

All but the firewall zone and applies to intrazone traffic.

net:^CN

China.

loc:(eth1:1.2.3.4,2.3.4.5),dmz:(eth2:5.6.7.8,9.10.11.12),net

Hosts 1.2.3.4 and 2.3.4.5 in the loc zone when the packet arrives through eth1 plus hosts 5.6.7.8 and 9.10.11.12 in the dmz zone when the packet arrives through eth2 plus all of the net zone.

dmz:[2002:ce7c:2b4:1::2]

Host 2002:ce7c:92b4:1::2 in the DMZ

net:2001:4d48:ad51:24::/64

Subnet 2001:4d48:ad51:24::/64 on the Internet

loc:[2002:cec792b4:1::2],[2002:cec792b4:1::44]

Hosts 2002:cec792b4:1::2 and 2002:cec792b4:1::44 in the local zone.

loc:~00-A0-C9-15-39-78

Host in the local zone with MAC address 00:A0:C9:15:39:78.

net:[2001:4d48:ad51:24::]/64![2001:4d48:ad51:24:6::]/80

Subnet 2001:4d48:ad51:24::/64 on the Internet except for 2001:4d48:ad51:24:6::/80.

DEST - dest-spec[,...]

Destination hosts to which the rule applies. dest-spec is one of the following:

zone[,...[+]]

The name of a zone defined in shorewall-zones[4](5). When only the zone name is specified, the packet destination may be any host in that zone. zone may also be one of the following:

all[+]

all, without the "-" means "All Zones, including the firewall zone". Normally all omits intra-zone traffic, but intra-zone traffic can be included specifying "+".

any[+]

any is equivalent to all when there are no nested zones. When there are nested zones, any only refers to top-level zones (those with no parent zones). Note that any excludes all vserver zones, since those zones are nested within the firewall zone.

none

When none is used either in the SOURCE or DEST column, the rule is ignored.

Similar to with all and any, intra-zone traffic is normally excluded when multiple zones are listed. Intra-zone traffic may be included by following the list with a plus sign ("+").

all and any may be followed by an exclamation point ("!") and a comma-separated list of zone names to be omitted.

zone:[!]interface

When this form is used, interface must be the name of an interface associated with the named zone in either shorewall-interfaces[8](5) or shorewall-hosts[11](5). Only packets to hosts in the zone that are sent through the named interface will match the rule. Beginning with Shorweall 5.2.1, the interface may be preceded with '!' which matches all interfaces associated with the zone except the one specified.

zone:address[,...]

where address can be:

•A host or network IP address. A network address may be followed by exclusion (see shorewall-exclusion[10](5)).

•An address range, specified using the syntax lowaddress-highaddress.

•+ipset where ipset is the name of an ipset and must be preceded by a plus sign ("+").

•^country-code where country-code is a two-character ISO-3661 country code preceded by a caret ("^").

•^country-code-list where country-code-list is a comma-separated list of up to 15 ISO-3661 country codes enclosed in square brackets ("[...]").

•The primary IP address of a firewall interface can be specified by an ampersand ('&') followed by the logical name of the interface as found in the INTERFACE column of shorewall-interfaces[8] (5).

zone:[!]interface:address[,...]

This form combines the preceding two and requires that both the outgoing interface and destinationaddress match. Beginning with Shorweall 5.2.1, the interface may be preceded with '!' which matches all interfaces associated with the zone except the one specified.

zone:exclusion

This form matches if the host IP address does not match any of the entries in the exclusion (see shorewall-exclusion[10](5)).

zone:[!]interface:exclusion

This form matches packets to the named zone leaving through the specified interface where the destination address does not match any entry in the exclusion. Beginning with Shorweall 5.2.1, the interface may be preceded with '!' which matches all interfaces associated with the zone except the one specified.

[zone]:[server-IP][:port-or-port-range[:random]]

This form applies when the ACTION is DNAT[-] or REDIRECT[-]. The zone may be omitted in REDIRECT rules ($FW is assumed) and must be omitted in DNAT-, REDIRECT- and NONAT rules. server-IP is not allowed in REDIRECT rules and may be omitted in DNAT[-] rules provided that port-or-port-range is included.

•The IP address of the server to which the packet is to be sent.

•A range of IP address with the low and high address separated by a dash (:"-"). Connections are distributed among the IP addresses in the range.

If server-IP is omitted in a DNAT[-] rule, only the destination port number is modified by the rule.

port-or-port-range may be:

•An integer port number in the range 1 - 65535.

•The name of a service from /etc/services.

•A port range with the low and high integer port numbers separated by a dash ("-"). Connections are distributed among the ports in the range.

If random is specified, port mapping will be randomized.

If the DEST zone is a bport zone, then either:

1.the SOURCE must be all[+], or

2.the SOURCE zone must be another bport zone associated with the same bridge, or

3.the SOURCE zone must be an ipv4 zone that is associated with only the same bridge.

Beginning with Shorewall 5.1.0, multiple dest-specs may be listed, provided that extended forms of the source-spec are used: zone:(interface)

zone:(address[,...])

zone:(interface:address[,...])

zone:(exclusion)

zone:(interface:exclusion) Multiple dest-specs are not permitted in DNAT[-] and REDIRECT[-] rules.

Examples:

dmz:192.168.2.2

Host 192.168.2.2 in the DMZ

net:155.186.235.0/24

Subnet 155.186.235.0/24 on the Internet

loc:192.168.1.1,192.168.1.2

Hosts 192.168.1.1 and 192.168.1.2 in the local zone.

net:192.0.2.11-192.0.2.17

Hosts 192.0.2.11-192.0.2.17 in the net zone.

net:!192.0.2.11-192.0.2.17

All hosts in the net zone except for 192.0.2.11-192.0.2.17.

net:155.186.235.0/24!155.186.235.16/28

Subnet 155.186.235.0/24 on the Internet except for 155.186.235.16/28

$FW:&eth0

The primary IP address of eth0 in the firewall zone.

loc,dmz

Both the loc and dmz zones.

all!dmz

All but the dmz zone.

net:^CN

China.

dmz:192.168.10.4:25

Port 25 on server 192.168.10.4 in the dmz zone (DNAT rule).

loc:(eth1:1.2.3.4,2.3.4.5),dmz:(eth2:5.6.7.8,9.10.11.12),net

Hosts 1.2.3.4 and 2.3.4.5 in the loc zone when the packet arrives through eth1 plus hosts 5.6.7.8 and 9.10.11.12 in the dmz zone when the packet arrives through eth2 plus all of the net zone.

PROTO- {-|tcp:[!]syn|ipp2p|ipp2p:udp|ipp2p:all|protocol-number|protocol-name|all}

Optional Protocol - ipp2p* requires ipp2p match support in your kernel and iptables. tcp:syn implies tcp plus the SYN flag must be set and the RST, ACK and FIN flags must be reset. Beginning with Shorewall 5.1.3, you may also specify tcp:!syn, which matches if SYN is not set or if RST, ACK or FIN is set. Beginning with Shorewall 4.4.19, this column can contain a comma-separated list of protocol-numbers and/or protocol names.

DPORT - {-|port-name-number-or-range[,port-name-number-or-range]...|+ipset}

Optional destination Ports. A comma-separated list of Port names (from services(5)), port numbers or port ranges; if the protocol is icmp, this column is interpreted as the destination icmp-type(s). ICMP types may be specified as a numeric type, a numeric type and code separated by a slash (e.g., 3/4), or a typename. See https://shorewall.org/configuration_file_basics.htm#ICMP[12]. Note that prior to Shorewall 4.4.19, only a single ICMP type may be listed. If the protocol is ipp2p, this column is interpreted as an ipp2p option without the leading "--" (example bit for bit-torrent). If no port is given, ipp2p is assumed.

A port range is expressed as lowport:highport.

This column is ignored if PROTO = all but must be entered if any of the following columns are supplied. In that case, it is suggested that this field contain a dash (-).

If your kernel contains multi-port match support, then only a single Netfilter rule will be generated if in this list and the SPORT list below:

1. There are 15 or less ports listed.

2. No port ranges are included or your kernel and iptables contain extended multi-port match support.

Beginning with Shorewall 4.6.0, an ipset name can be specified in this column. This is intended to be used with bitmap:port ipsets.

This column was formerly labelled DEST PORT(S).

SPORT - {-|port-name-number-or-range[,port-name-number-or-range]...|+ipset}

Optional port(s) used by the client. If omitted, any source port is acceptable. Specified as a comma- separated list of port names, port numbers or port ranges. Beginning with Shorewall 4.5.15, you may place '=' in this column, provided that the DPORT column is non-empty. This causes the rule to match when either the source port or the destination port in a packet matches one of the ports specified in DEST PORTS(S). Use of '=' requires multi-port match in your iptables and kernel.

Warning

Unless you really understand IP, you should leave this column empty or place a dash (-) in the column. Most people who try to use this column get it wrong.

If you don't want to restrict client ports but need to specify an ORIGDEST in the next column, then place "-" in this column. If your kernel contains multi-port match support, then only a single Netfilter rule will be generated if in this list and the DPORT list above:

1. There are 15 or less ports listed.

2. No port ranges are included or your kernel and iptables contain extended multi-port match support.

Beginning with Shorewall 4.6.0, an ipset name can be specified in this column. This is intended to be used with bitmap:port ipsets.

This column was formerly labelled SOURCE PORT(S).

ORIGDEST - [-|address[,address]...[exclusion]|exclusion]

Optional. If ACTION is DNAT[-] or REDIRECT[-] then if this column is included and is different from the IP address given in the DEST column, then connections destined for that address will be forwarded to the IP and port specified in the DEST column. A comma-separated list of addresses may also be used. This is most useful with the REDIRECT target where you want to redirect traffic destined for particular set of hosts. Finally, if the list of addresses begins with "!" (exclusion) then the rule will be followed only if the original destination address in the connection request does not match any of the addresses listed.

Beginning with Shorewall 4.4.17, the primary IP address of a firewall interface can be specified by an ampersand ('&') followed by the logical name of the interface as found in the INTERFACE column of shorewall-interfaces[8] (5).

For other actions, this column may be included and may contain one or more addresses (host or network) separated by commas. Address ranges are not allowed. When this column is supplied, rules are generated that require that the original destination address matches one of the listed addresses. This feature is most useful when you want to generate a filter rule that corresponds to a DNAT- or REDIRECT- rule. In this usage, the list of addresses should not begin with "!".

It is also possible to specify a set of addresses then exclude part of those addresses. For example, 192.168.1.0/24!192.168.1.16/28 specifies the addresses 192.168.1.0-182.168.1.15 and 192.168.1.32-192.168.1.255. See shorewall-exclusion[10](5).

See https://shorewall.org/PortKnocking.html[13] for an example of using an entry in this column with a user-defined action rule.

This column was formerly labelled ORIGINAL DEST.

RATE - limit

where limit is one of: [-|[{s|d}[/vlsm]:[name[(ht-buckets,ht-max)]:]rate/{sec|min|hour|day}[:burst]

[s[/vlsm1]:][name1[(ht-buckets1,ht-max1)]:]rate1/{sec|min|hour|day}[:burst1],[d[/vlsm2:][name2[(ht-buckets2,ht-max2)]:]rate2/{sec|min|hour|day}[:burst2]

You may optionally rate-limit the rule by placing a value in this column: rate* is the number of connections per interval (sec or min) and burst* is the largest burst permitted. If no burst is given, a value of 5 is assumed. There may be no no white-space embedded in the specification.

Example: 10/sec:20

When s: or d: is specified, the rate applies per source IP address or per destination IP address respectively. The names may be chosen by the user and specify a hash table to be used to count matching connections. If not given, the name shorewallN (where N is a unique integer) is assumed. Where more than one rule or POLICY specifies the same name, the connections counts for the rules are aggregated and the individual rates apply to the aggregated count. Beginning with Shorewall 5.2.1, the s or d may be followed by a slash ("/") and an integer vlsm. When a vlsm is specified, all source or destination addresses encountered will be grouped according to the given prefix length and the so-created subnet will be subject to the rate limit.

Example: s/24::10/sec

Beginning with Shorewall 4.6.5, two limits may be specified, separated by a comma. In this case, the first limit (name1, rate1, burst1) specifies the per-source IP limit and the second limit specifies the per-destination IP limit.

Example: client:10/sec:20,:60/sec:100

In this example, the 'client' hash table will be used to enforce the per-source limit and the compiler will pick a unique name for the hash table that tracks the per-destination limit.

Beginning with Shorewall 5.2.1, the table name, if any, may be followed by two integers separated by commas and enclosed in parentheses. The first integer (ht-buckets) specifies the number of buckets in the generated hash table. The second integer (ht-max) specifies the maximum number of entries in the hash table.

Example: s:netfw(1024,65536):10/sec

This column was formerly labelled RATE LIMIT.

USER - [!][user-name-or-number][:group-name-or-number][,...]

This optional column may only be non-empty if the SOURCE is the firewall itself. When this column is non-empty, the rule applies only if the program generating the output is running under the effective user and/or group specified (or is NOT running under that id if "!" is given).

Beginning with Shorewall 4.5.8, multiple user or group names/ids separated by commas may be specified.

Examples:

joe

program must be run by joe

:kids

program must be run by a member of the 'kids' group

!:kids

program must not be run by a member of the 'kids' group

2001-2099

UIDs 2001 through 2099 (Shorewall 4.5.6 and later)

This column was formerly labelled USER/GROUP.

MARK - [!]value[/mask][:C]

Defines a test on the existing packet or connection mark. The rule will match only if the test returns true. If you don't want to define a test but need to specify anything in the following columns, place a "-" in this field.

!

Inverts the test (not equal)

value

Value of the packet or connection mark.

mask

A mask to be applied to the mark before testing.

:C

Designates a connection mark. If omitted, the packet mark's value is tested.

CONNLIMIT - [d:][!]limit[:mask]

May be used to limit the number of simultaneous connections to/from each individual host or network to limit connections. Requires connlimit match in your kernel and iptables. While the limit is only checked on rules specifying CONNLIMIT, the number of current connections is calculated over all current connections from the SOURCE or DESTINATION host. By default, limiting is done by SOURCE host or net, but if the specification begins with d:, then limiting will be donw by destination host or net. By default, the limit is applied to each host but can be made to apply to networks of hosts by specifying a mask. The mask specifies the width of a VLSM mask to be applied to the source address; the number of current connections is then taken over all hosts in the subnet source-address/mask. When ! is specified, the rule matches when the number of connection exceeds the limit.

TIME - timeelement[&timeelement...]

May be used to limit the rule to a particular time period each day, to particular days of the week or month, or to a range defined by dates and times. Requires time match support in your kernel and iptables. timeelement may be:

timestart=hh:mm[:ss]

Defines the starting time of day.

timestop=hh:mm[:ss]

Defines the ending time of day.

contiguous

Added in Shoreawll 5.0.12. When timestop is smaller than timestart value, match this as a single time period instead of distinct intervals.

utc

Times are expressed in Greenwich Mean Time.

localtz

Deprecated by the Netfilter team in favor of kerneltz. Times are expressed in Local Civil Time (default).

kerneltz

Added in Shorewall 4.5.2. Times are expressed in Local Kernel Time (requires iptables 1.4.12 or later).

weekdays=ddd[,ddd]...

where ddd is one of Mon, Tue, Wed, Thu, Fri, Sat or Sun

monthdays=dd[,dd],...

where dd is an ordinal day of the month

datestart=yyyy[-mm[-dd[Thh[:mm[:ss]]]]]

Defines the starting date and time.

datestop=yyyy[-mm[-dd[Thh[:mm[:ss]]]]]

Defines the ending date and time.

HEADERS - [!][any:|exactly:]header-list (Optional - Added in Shorewall 4.4.15)

This column is only used in IPv6. In IPv4, supply "-" in this column if you with to place a value in one of the following columns. The header-list consists of a comma-separated list of headers from the following list.

auth, ah, or 51

Authentication Headers extension header.

esp, or 50

Encrypted Security Payload extension header.

hop, hop-by-hop or 0

Hop-by-hop options extension header.

route, ipv6-route or 43

IPv6 Route extension header.

frag, ipv6-frag or 44

IPv6 fragmentation extension header.

none, ipv6-nonxt or 59

No next header

proto, protocol or 255

Any protocol header.

If any: is specified, the rule will match if any of the listed headers are present. If exactly: is specified, the will match packets that exactly include all specified headers. If neither is given, any: is assumed.

If ! is entered, the rule will match those packets which would not be matched when ! is omitted.

SWITCH - [!]switch-name[={0|1}]

Added in Shorewall 4.4.24 and allows enabling and disabling the rule without requiring shorewall reload. The rule is enabled if the value stored in /proc/net/nf_condition/switch-name is 1. The rule is disabled if that file contains 0 (the default). If '!' is supplied, the test is inverted such that the rule is enabled if the file contains 0.

Within the switch-name, '@0' and '@{0}' are replaced by the name of the chain to which the rule is a added. The switch-name (after '@...' expansion) must begin with a letter and be composed of letters, decimal digits, underscores or hyphens. Switch names must be 30 characters or less in length.

Switches are normally off. To turn a switch on:

echo 1 >

/proc/net/nf_condition/switch-name

To turn it off again: echo 0 >

/proc/net/nf_condition/switch-name

Switch settings are retained over shorewall reload. Beginning with Shorewall 4.5.10, when the switch-name is followed by =0 or =1, then the switch is initialized to off or on respectively by the start command. Other commands do not affect the switch setting.

HELPER - [helper]

Added in Shorewall 4.5.7. In the NEW section, causes the named conntrack helper to be associated with this connection; the contents of this column are ignored unless ACTION is ACCEPT*, DNAT* or REDIRECT*.

In the RELATED section, will only match if the related connection has the named helper associated with it.

The helper may be one of:

amanda

ftp

irc

netbios-ns

pptp

Q.931

RAS

sane

sip

snmp

tftp

If the HELPERS option is specified in shorewall.conf[2](5), then any module specified in this column must be listed in the HELPERS setting.

## EXAMPLES
Example 1:

Accept SMTP requests from the DMZ to the internet

```
         #ACTION SOURCE  DEST      PROTO      DPORT   SPORT   ORIGDEST

         ACCEPT  dmz     net       tcp        smtp
```

Example 2:

Forward all ssh and http connection requests from the internet to local system 192.168.1.3

```
        #ACTION SOURCE  DEST            PROTO   DPORT   SPORT   ORIGDEST

        DNAT    net     loc:192.168.1.3 tcp     ssh,http
```

Example 3:

Forward all http connection requests from the internet to local system 192.168.1.3 with a limit of 3 per second and a maximum burst of 10

```
        #ACTION SOURCE DEST             PROTO  DPORT SPORT   ORIGDEST RATE

        DNAT    net    loc:192.168.1.3  tcp    http  -       -        3/sec:10
```

Example 4:

Redirect all locally-originating www connection requests to port 3128 on the firewall (Squid running on the firewall system) except when the destination address is 192.168.2.2

```
        #ACTION  SOURCE DEST      PROTO DPORT   SPORT   ORIGDEST

        REDIRECT loc    3128      tcp   www      -      !192.168.2.2
```

Example 5:

All http requests from the internet to address 130.252.100.69 are to be forwarded to 192.168.1.3

```
        #ACTION  SOURCE DEST            PROTO   DPORT   SPORT   ORIGDEST

        DNAT      net   loc:192.168.1.3 tcp     80      -       130.252.100.69
```

Example 6:

You want to accept SSH connections to your firewall only from internet IP addresses 130.252.100.69 and 130.252.100.70

```
        #ACTION  SOURCE DEST            PROTO   DPORT   SPORT   ORIGDEST

        ACCEPT   net:130.252.100.69,130.252.100.70 \

                        $FW             tcp     22
```

Example 7:

You wish to accept connections from the internet to your firewall on port 2222 and you want to forward them to local system 192.168.1.3, port 22

```
        #ACTION  SOURCE DEST                PROTO   DPORT   SPORT   ORIGDEST

        DNAT     net    loc:192.168.1.3:22  tcp     2222
```

Example 8:

You want to redirect connection requests to port 80 randomly to the port range 81-90.

```
        #ACTION  SOURCE DEST                PROTO DPORT   SPORT   ORIGDEST

        REDIRECT net    $FW::81-90:random   tcp   www
```

Example 9:

Shorewall does not impose as much structure on the Netfilter rules in the 'nat' table as it does on those in the filter table. As a consequence, when using Shorewall versions before 4.1.4, care must be exercised when using DNAT and REDIRECT rules with zones defined with wildcard interfaces (those ending with '+'. Here is an example: shorewall-zones[4](5):

```
        #ZONE       TYPE    OPTIONS

        fw          firewall

        net         ipv4

        dmz         ipv4

        loc         ipv4
```

shorewall-interfaces[8](5):

```
        #ZONE       INTERFACE       BROADCAST      OPTIONS

        net         ppp0

        loc         eth1            detect

        dmz         eth2            detect

        -           ppp+                           # Addresses are assigned from 192.168.3.0/24
```

shorewall-host[11](5):

```
        #ZONE       HOST(S)              OPTIONS

        loc         ppp+:192.168.3.0/24
```

rules:

```
        #ACTION     SOURCE          DEST       PROTO       DPORT

        REDIRECT    loc             3128       tcp         80
```

Note that it would have been tempting to simply define the loc zone entirely in shorewall-interfaces(8):

```
        #******************* INCORRECT *****************

        #ZONE       INTERFACE       BROADCAST      OPTIONS

        net         ppp0

        loc         eth1            detect

        loc         ppp+

        dmz         eth2
```

This would have made it impossible to run a internet-accessible web server in the DMZ because all traffic entering ppp+ interfaces would have been redirected to port 3128 on the firewall and there would have been no net->fw ACCEPT rule for that traffic.

Example 10:

Add the tuple (source IP, dest port, dest IP) of an incoming SSH connection to the ipset S:

```
        #ACTION                       SOURCE           DEST           PROTO       DPORT

        ADD(+S:dst,src,dst)           net              fw             tcp         22
```

Example 11:

You wish to limit SSH connections from remote systems to 1/min with a burst of three (to allow for limited retry):

```
        #ACTION     SOURCE          DEST       PROTO       DPORT        SPORT     ORIGDEST         RATE

        SSH(ACCEPT) net             all        -           -            -         -                s:1/min:3
```

Example 12:

Forward port 80 to dmz host $BACKUP if switch 'primary_down' is on.

```
        #ACTION     SOURCE          DEST        PROTO       DPORT        SPORT     ORIGDEST   RATE      USER      MARK    CONNLIMIT     TIME     HEADERS    SWITCH

        DNAT        net             dmz:$BACKUP tcp         80           -         -          -         -         -       -             -        -          primary_down
```

Example 13:

Drop all email from the Anonymous Proxy and Satellite Provider address ranges:

```
        #ACTION                       SOURCE           DEST           PROTO       DPORT

        DROP                          net:^A1,A2       fw             tcp         25
```

Example 14:

You want to generate your own rule involving iptables targets and matches not supported by Shorewall.

```
        #ACTION                       SOURCE           DEST           PROTO       DPORT

        INLINE                        $FW              net ; -p 6 -m mickey-mouse --name test -m set --match-set set1 src -m mickey-mouse --name test2 -j SECCTX --name test3
```

The above will generate the following iptables-restore input:

```
        -A fw2net -p 6 -m mickey-mouse --name test -m set --match-set set1 src -m mickey-mouse --name test2 -j SECCTX --name test3
```

Note that SECCTX must be defined as a builtin action in shorewall-actions[3](5):

```
        #ACTION            OPTIONS

        SECCTX             builtin
```

Example 15:

You want to accept SSH connections to your firewall only from internet IP addresses 2002:ce7c::92b4:1::2 and 2002:ce7c::92b4:1::22

```
        #ACTION  SOURCE DEST            PROTO   DPORT   SPORT   ORIGDEST

        ACCEPT   net:<2002:ce7c::92b4:1::2,2002:ce7c::92b4:1::22> \

                        $FW              tcp     22
```

## FILES
/etc/shorewall/rules

/etc/shorewall6/rules

## SEE ALSO
shorewall-logging(5)[7]

https://shorewall.org/ipsets.html[14]

https://shorewall.org/configuration_file_basics.htm#Pairs[15]

shorewall(8)

## NOTES
1.

shorewall-policy

https://shorewall.org/manpages/shorewall-policy.html

2.

shorewall.conf

https://shorewall.org/manpages/shorewall.conf.html

3.

shorewall-actions

https://shorewall.org/manpages/shorewall-actions.html

4.

shorewall-zones

https://shorewall.org/manpages/shorewall-zones.html

5.

shorewall-nesting

https://shorewall.org/manpages/shorewall-nesting.html

6.

https://shorewall.org/shorewall_logging.html

https://shorewall.org/shorewall_logging.html

7.

shorewall-logging(5)

https://shorewall.org/manpages/shorewall-logging.html

8.

shorewall-interfaces

https://shorewall.org/manpages/shorewall-interfaces.html

9.

shorewall-hosts

https://shorewall.org/manpages/shorewall.hosts.html

10.

shorewall-exclusion

https://shorewall.org/manpages/shorewall-exclusion.html

11.

shorewall-hosts

https://shorewall.org/manpages/shorewall-hosts.html

12.

https://shorewall.org/configuration_file_basics.htm#ICMP

https://shorewall.org/configuration_file_basics.htm#ICMP

13.

https://shorewall.org/PortKnocking.html

https://shorewall.org/PortKnocking.html

14.

https://shorewall.org/ipsets.html

https://shorewall.org/ipsets.html

15.

https://shorewall.org/configuration_file_basics.htm#Pairs

https://shorewall.org/configuration_file_basics.htm#Pairs