IPv4 Firewall Configuration

Overview

In this section there’s useful information of all firewall configuration that can be done regarding IPv4, and appropriate op-mode commands. Configuration commands covered in this section:

set firewall ipv4 …

From main structure defined in Firewall Overview in this section you can find detailed information only for the next part of the general structure:

- set firewall
    * ipv4
         - forward
            + filter
         - input
            + filter
         - output
            + filter
            + raw
         - prerouting
            + raw
         - name
            + custom_name

First, all traffic is received by the router, and it is processed in the prerouting section.

This stage includes:

  • Firewall Prerouting: commands found under set firewall ipv4 prerouting raw ...

  • Conntrack Ignore: set system conntrack ignore ipv4...

  • Policy Route: commands found under set policy route ...

  • Destination NAT: commands found under set nat destination ...

For transit traffic, which is received by the router and forwarded, base chain is forward. A simplified packet flow diagram for transit traffic is shown next:

../../_images/firewall-fwd-packet-flow.png

Firewall base chain to configure firewall filtering rules for transit traffic is set firewall ipv4 forward filter ..., which happens in stage 5, highlighted with red color.

For traffic towards the router itself, base chain is input, while traffic originated by the router, base chain is output. A new simplified packet flow diagram is shown next, which shows the path for traffic destined to the router itself, and traffic generated by the router (starting from circle number 6):

../../_images/firewall-input-packet-flow.png

Base chain for traffic towards the router is set firewall ipv4 input filter ...

And base chain for traffic generated by the router is set firewall ipv4 output ..., where two sub-chains are available: filter and raw:

  • Output Prerouting: set firewall ipv4 output raw .... As described in Prerouting, rules defined in this section are processed before connection tracking subsystem.

  • Output Filter: set firewall ipv4 output filter .... Rules defined in this section are processed after connection tracking subsystem.

Note

Important note about default-actions: If default action for any base chain is not defined, then the default action is set to accept for that chain. For custom chains, if default action is not defined, then the default-action is set to drop

Custom firewall chains can be created, with commands set firewall ipv4 name <name> .... In order to use such custom chain, a rule with action jump, and the appropriate target should be defined in a base chain.

Firewall - IPv4 Rules

For firewall filtering, firewall rules needs to be created. Each rule is numbered, has an action to apply if the rule is matched, and the ability to specify multiple criteria matchers. Data packets go through the rules from 1 - 999999, so order is crucial. At the first match the action of the rule will be executed.

Actions

If a rule is defined, then an action must be defined for it. This tells the firewall what to do if all criteria matchers defined for such rule do match.

The action can be :

  • accept: accept the packet.

  • continue: continue parsing next rule.

  • drop: drop the packet.

  • reject: reject the packet.

  • jump: jump to another custom chain.

  • return: Return from the current chain and continue at the next rule of the last chain.

  • queue: Enqueue packet to userspace.

  • synproxy: synproxy the packet.

set firewall ipv4 forward filter rule <1-999999> action [accept | continue | drop | jump | queue | reject | return | synproxy]
set firewall ipv4 input filter rule <1-999999> action [accept | continue | drop | jump | queue | reject | return | synproxy]
set firewall ipv4 output filter rule <1-999999> action [accept | continue | drop | jump | queue | reject | return]
set firewall ipv4 name <name> rule <1-999999> action [accept | continue | drop | jump | queue | reject | return]

This required setting defines the action of the current rule. If action is set to jump, then jump-target is also needed.

set firewall ipv4 forward filter rule <1-999999> jump-target <text>
set firewall ipv4 input filter rule <1-999999> jump-target <text>
set firewall ipv4 output filter rule <1-999999> jump-target <text>
set firewall ipv4 name <name> rule <1-999999> jump-target <text>

To be used only when action is set to jump. Use this command to specify jump target.

set firewall ipv4 forward filter rule <1-999999> queue <0-65535>
set firewall ipv4 input filter rule <1-999999> queue <0-65535>
set firewall ipv4 output filter rule <1-999999> queue <0-65535>
set firewall ipv4 name <name> rule <1-999999> queue <0-65535>

To be used only when action is set to queue. Use this command to specify queue target to use. Queue range is also supported.

set firewall ipv4 forward filter rule <1-999999> queue-options bypass
set firewall ipv4 input filter rule <1-999999> queue-options bypass
set firewall ipv4 output filter rule <1-999999> queue-options bypass
set firewall ipv4 name <name> rule <1-999999> queue-options bypass

To be used only when action is set to queue. Use this command to let packet go through firewall when no userspace software is connected to the queue.

set firewall ipv4 forward filter rule <1-999999> queue-options fanout
set firewall ipv4 input filter rule <1-999999> queue-options fanout
set firewall ipv4 output filter rule <1-999999> queue-options fanout
set firewall ipv4 name <name> rule <1-999999> queue-options fanout

To be used only when action is set to queue. Use this command to distribute packets between several queues.

Also, default-action is an action that takes place whenever a packet does not match any rule in it’s chain. For base chains, possible options for default-action are accept or drop.

set firewall ipv4 forward filter default-action [accept | drop]
set firewall ipv4 input filter default-action [accept | drop]
set firewall ipv4 output filter default-action [accept | drop]
set firewall ipv4 name <name> default-action [accept | drop | jump | queue | reject | return]

This set the default action of the rule-set if no rule matched a packet criteria. If default-action is set to jump, then default-jump-target is also needed. Note that for base chains, default action can only be set to accept or drop, while on custom chain, more actions are available.

set firewall ipv4 name <name> default-jump-target <text>

To be used only when default-action is set to jump. Use this command to specify jump target for default rule.

Note

Important note about default-actions: If default action for any base chain is not defined, then the default action is set to accept for that chain. For custom chains, if default action is not defined, then the default-action is set to drop.

Firewall Logs

Logging can be enable for every single firewall rule. If enabled, other log options can be defined.

set firewall ipv4 forward filter rule <1-999999> log
set firewall ipv4 input filter rule <1-999999> log
set firewall ipv4 output filter rule <1-999999> log
set firewall ipv4 name <name> rule <1-999999> log

Enable logging for the matched packet. If this configuration command is not present, then log is not enabled.

set firewall ipv4 forward filter default-log
set firewall ipv4 input filter default-log
set firewall ipv4 output filter default-log
set firewall ipv4 name <name> default-log

Use this command to enable the logging of the default action on the specified chain.

set firewall ipv4 forward filter rule <1-999999> log-options level [emerg | alert | crit | err | warn | notice | info | debug]
set firewall ipv4 input filter rule <1-999999> log-options level [emerg | alert | crit | err | warn | notice | info | debug]
set firewall ipv4 output filter rule <1-999999> log-options level [emerg | alert | crit | err | warn | notice | info | debug]
set firewall ipv4 name <name> rule <1-999999> log-options level [emerg | alert | crit | err | warn | notice | info | debug]

Define log-level. Only applicable if rule log is enable.

set firewall ipv4 forward filter rule <1-999999> log-options group <0-65535>
set firewall ipv4 input filter rule <1-999999> log-options group <0-65535>
set firewall ipv4 output filter rule <1-999999> log-options group <0-65535>
set firewall ipv4 name <name> rule <1-999999> log-options group <0-65535>

Define log group to send message to. Only applicable if rule log is enable.

set firewall ipv4 forward filter rule <1-999999> log-options snapshot-length <0-9000>
set firewall ipv4 input filter rule <1-999999> log-options snapshot-length <0-9000>
set firewall ipv4 output filter rule <1-999999> log-options snapshot-length <0-9000>
set firewall ipv4 name <name> rule <1-999999> log-options snapshot-length <0-9000>

Define length of packet payload to include in netlink message. Only applicable if rule log is enable and log group is defined.

set firewall ipv4 forward filter rule <1-999999> log-options queue-threshold <0-65535>
set firewall ipv4 input filter rule <1-999999> log-options queue-threshold <0-65535>
set firewall ipv4 output filter rule <1-999999> log-options queue-threshold <0-65535>
set firewall ipv4 name <name> rule <1-999999> log-options queue-threshold <0-65535>

Define number of packets to queue inside the kernel before sending them to userspace. Only applicable if rule log is enable and log group is defined.

Firewall Description

For reference, a description can be defined for every single rule, and for every defined custom chain.

set firewall ipv4 name <name> description <text>

Provide a rule-set description to a custom firewall chain.

set firewall ipv4 forward filter rule <1-999999> description <text>
set firewall ipv4 input filter rule <1-999999> description <text>
set firewall ipv4 output filter rule <1-999999> description <text>
set firewall ipv4 name <name> rule <1-999999> description <text>

Provide a description for each rule.

Rule Status

When defining a rule, it is enable by default. In some cases, it is useful to just disable the rule, rather than removing it.

set firewall ipv4 forward filter rule <1-999999> disable
set firewall ipv4 input filter rule <1-999999> disable
set firewall ipv4 output filter rule <1-999999> disable
set firewall ipv4 name <name> rule <1-999999> disable

Command for disabling a rule but keep it in the configuration.

Matching criteria

There are a lot of matching criteria against which the packet can be tested.

set firewall ipv4 forward filter rule <1-999999> connection-status nat [destination | source]
set firewall ipv4 input filter rule <1-999999> connection-status nat [destination | source]
set firewall ipv4 output filter rule <1-999999> connection-status nat [destination | source]
set firewall ipv4 name <name> rule <1-999999> connection-status nat [destination | source]

Match criteria based on nat connection status.

set firewall ipv4 forward filter rule <1-999999> connection-mark <1-2147483647>
set firewall ipv4 input filter rule <1-999999> connection-mark <1-2147483647>
set firewall ipv4 output filter rule <1-999999> connection-mark <1-2147483647>
set firewall ipv4 name <name> rule <1-999999> connection-mark <1-2147483647>

Match criteria based on connection mark.

set firewall ipv4 forward filter rule <1-999999> conntrack-helper <module>
set firewall ipv4 input filter rule <1-999999> conntrack-helper <module>
set firewall ipv4 output filter rule <1-999999> conntrack-helper <module>
set firewall ipv4 name <name> rule <1-999999> conntrack-helper <module>

Match based on connection tracking protocol helper module to secure use of that helper module. See below for possible completions <module>.

Possible completions:
ftp                  Related traffic from FTP helper
h323                 Related traffic from H.323 helper
pptp                 Related traffic from PPTP helper
nfs                  Related traffic from NFS helper
sip                  Related traffic from SIP helper
tftp                 Related traffic from TFTP helper
sqlnet               Related traffic from SQLNet helper
set firewall ipv4 forward filter rule <1-999999> source address [address | addressrange | CIDR]
set firewall ipv4 input filter rule <1-999999> source address [address | addressrange | CIDR]
set firewall ipv4 output filter rule <1-999999> source address [address | addressrange | CIDR]
set firewall ipv4 name <name> rule <1-999999> source address [address | addressrange | CIDR]
set firewall ipv4 forward filter rule <1-999999> destination address [address | addressrange | CIDR]
set firewall ipv4 input filter rule <1-999999> destination address [address | addressrange | CIDR]
set firewall ipv4 output filter rule <1-999999> destination address [address | addressrange | CIDR]
set firewall ipv4 name <name> rule <1-999999> destination address [address | addressrange | CIDR]

Match criteria based on source and/or destination address. This is similar to the network groups part, but here you are able to negate the matching addresses.

set firewall ipv4 name FOO rule 50 source address 192.0.2.10-192.0.2.11
# with a '!' the rule match everything except the specified subnet
set firewall ipv4 input filter FOO rule 51 source address !203.0.113.0/24
set firewall ipv4 forward filter rule <1-999999> source address-mask [address]
set firewall ipv4 input filter rule <1-999999> source address-mask [address]
set firewall ipv4 output filter rule <1-999999> source address-mask [address]
set firewall ipv4 name <name> rule <1-999999> source address-mask [address]
set firewall ipv4 forward filter rule <1-999999> destination address-mask [address]
set firewall ipv4 input filter rule <1-999999> destination address-mask [address]
set firewall ipv4 output filter rule <1-999999> destination address-mask [address]
set firewall ipv4 name <name> rule <1-999999> destination address-mask [address]

An arbitrary netmask can be applied to mask addresses to only match against a specific portion.

This functions for both individual addresses and address groups.

# Match any IPv4 address with `11` as the 2nd octet and `13` as the forth octet
set firewall ipv4 name FOO rule 100 destination address 0.11.0.13
set firewall ipv4 name FOO rule 100 destination address-mask 0.255.0.255
set firewall ipv4 forward filter rule <1-999999> source fqdn <fqdn>
set firewall ipv4 input filter rule <1-999999> source fqdn <fqdn>
set firewall ipv4 output filter rule <1-999999> source fqdn <fqdn>
set firewall ipv4 name <name> rule <1-999999> source fqdn <fqdn>
set firewall ipv4 forward filter rule <1-999999> destination fqdn <fqdn>
set firewall ipv4 input filter rule <1-999999> destination fqdn <fqdn>
set firewall ipv4 output filter rule <1-999999> destination fqdn <fqdn>
set firewall ipv4 name <name> rule <1-999999> destination fqdn <fqdn>

Specify a Fully Qualified Domain Name as source/destination matcher. Ensure router is able to resolve such dns query.

set firewall ipv4 forward filter rule <1-999999> source geoip country-code <country>
set firewall ipv4 input filter rule <1-999999> source geoip country-code <country>
set firewall ipv4 output filter rule <1-999999> source geoip country-code <country>
set firewall ipv4 name <name> rule <1-999999> source geoip country-code <country>
set firewall ipv4 forward filter rule <1-999999> destination geoip country-code <country>
set firewall ipv4 input filter rule <1-999999> destination geoip country-code <country>
set firewall ipv4 output filter rule <1-999999> destination geoip country-code <country>
set firewall ipv4 name <name> rule <1-999999> destination geoip country-code <country>
set firewall ipv4 forward filter rule <1-999999> source geoip inverse-match
set firewall ipv4 input filter rule <1-999999> source geoip inverse-match
set firewall ipv4 output filter rule <1-999999> source geoip inverse-match
set firewall ipv4 name <name> rule <1-999999> source geoip inverse-match
set firewall ipv4 forward filter rule <1-999999> destination geoip inverse-match
set firewall ipv4 input filter rule <1-999999> destination geoip inverse-match
set firewall ipv4 output filter rule <1-999999> destination geoip inverse-match
set firewall ipv4 name <name> rule <1-999999> destination geoip inverse-match

Match IP addresses based on its geolocation. More info: geoip matching. Use inverse-match to match anything except the given country-codes.

Data is provided by DB-IP.com under CC-BY-4.0 license. Attribution required, permits redistribution so we can include a database in images(~3MB compressed). Includes cron script (manually callable by op-mode update geoip) to keep database and rules updated.

set firewall ipv4 forward filter rule <1-999999> source mac-address <mac-address>
set firewall ipv4 input filter rule <1-999999> source mac-address <mac-address>
set firewall ipv4 output filter rule <1-999999> source mac-address <mac-address>
set firewall ipv4 name <name> rule <1-999999> source mac-address <mac-address>

Only in the source criteria, you can specify a mac-address.

set firewall ipv4 input filter rule 100 source mac-address 00:53:00:11:22:33
set firewall ipv4 input filter rule 101 source mac-address !00:53:00:aa:12:34
set firewall ipv4 forward filter rule <1-999999> source port [1-65535 | portname | start-end]
set firewall ipv4 input filter rule <1-999999> source port [1-65535 | portname | start-end]
set firewall ipv4 output filter rule <1-999999> source port [1-65535 | portname | start-end]
set firewall ipv4 name <name> rule <1-999999> source port [1-65535 | portname | start-end]
set firewall ipv4 forward filter rule <1-999999> destination port [1-65535 | portname | start-end]
set firewall ipv4 input filter rule <1-999999> destination port [1-65535 | portname | start-end]
set firewall ipv4 output filter rule <1-999999> destination port [1-65535 | portname | start-end]
set firewall ipv4 name <name> rule <1-999999> destination port [1-65535 | portname | start-end]

A port can be set with a port number or a name which is here defined: /etc/services.

set firewall ipv4 forward filter rule 10 source port '22'
set firewall ipv4 forward filter rule 11 source port '!http'
set firewall ipv4 forward filter rule 12 source port 'https'

Multiple source ports can be specified as a comma-separated list. The whole list can also be “negated” using !. For example:

set firewall ipv4 forward filter rule <1-999999> source group address-group <name | !name>
set firewall ipv4 input filter rule <1-999999> source group address-group <name | !name>
set firewall ipv4 output filter rule <1-999999> source group address-group <name | !name>
set firewall ipv4 name <name> rule <1-999999> source group address-group <name | !name>
set firewall ipv4 forward filter rule <1-999999> destination group address-group <name | !name>
set firewall ipv4 input filter rule <1-999999> destination group address-group <name | !name>
set firewall ipv4 output filter rule <1-999999> destination group address-group <name | !name>
set firewall ipv4 name <name> rule <1-999999> destination group address-group <name | !name>

Use a specific address-group. Prepend character ! for inverted matching criteria.

set firewall ipv4 forward filter rule <1-999999> source group dynamic-address-group <name | !name>
set firewall ipv4 input filter rule <1-999999> source group dynamic-address-group <name | !name>
set firewall ipv4 output filter rule <1-999999> source group dynamic-address-group <name | !name>
set firewall ipv4 name <name> rule <1-999999> source group dynamic-address-group <name | !name>
set firewall ipv4 forward filter rule <1-999999> destination group dynamic-address-group <name | !name>
set firewall ipv4 input filter rule <1-999999> destination group dynamic-address-group <name | !name>
set firewall ipv4 output filter rule <1-999999> destination group dynamic-address-group <name | !name>
set firewall ipv4 name <name> rule <1-999999> destination group dynamic-address-group <name | !name>

Use a specific dynamic-address-group. Prepend character ! for inverted matching criteria.

set firewall ipv4 forward filter rule <1-999999> source group network-group <name | !name>
set firewall ipv4 input filter rule <1-999999> source group network-group <name | !name>
set firewall ipv4 output filter rule <1-999999> source group network-group <name | !name>
set firewall ipv4 name <name> rule <1-999999> source group network-group <name | !name>
set firewall ipv4 forward filter rule <1-999999> destination group network-group <name | !name>
set firewall ipv4 input filter rule <1-999999> destination group network-group <name | !name>
set firewall ipv4 output filter rule <1-999999> destination group network-group <name | !name>
set firewall ipv4 name <name> rule <1-999999> destination group network-group <name | !name>

Use a specific network-group. Prepend character ! for inverted matching criteria.

set firewall ipv4 forward filter rule <1-999999> source group port-group <name | !name>
set firewall ipv4 input filter rule <1-999999> source group port-group <name | !name>
set firewall ipv4 output filter rule <1-999999> source group port-group <name | !name>
set firewall ipv4 name <name> rule <1-999999> source group port-group <name | !name>
set firewall ipv4 forward filter rule <1-999999> destination group port-group <name | !name>
set firewall ipv4 input filter rule <1-999999> destination group port-group <name | !name>
set firewall ipv4 output filter rule <1-999999> destination group port-group <name | !name>
set firewall ipv4 name <name> rule <1-999999> destination group port-group <name | !name>

Use a specific port-group. Prepend character ! for inverted matching criteria.

set firewall ipv4 forward filter rule <1-999999> source group domain-group <name | !name>
set firewall ipv4 input filter rule <1-999999> source group domain-group <name | !name>
set firewall ipv4 output filter rule <1-999999> source group domain-group <name | !name>
set firewall ipv4 name <name> rule <1-999999> source group domain-group <name | !name>
set firewall ipv4 forward filter rule <1-999999> destination group domain-group <name | !name>
set firewall ipv4 input filter rule <1-999999> destination group domain-group <name | !name>
set firewall ipv4 output filter rule <1-999999> destination group domain-group <name | !name>
set firewall ipv4 name <name> rule <1-999999> destination group domain-group <name | !name>

Use a specific domain-group. Prepend character ! for inverted matching criteria.

set firewall ipv4 forward filter rule <1-999999> source group mac-group <name | !name>
set firewall ipv4 input filter rule <1-999999> source group mac-group <name | !name>
set firewall ipv4 output filter rule <1-999999> source group mac-group <name | !name>
set firewall ipv4 name <name> rule <1-999999> source group mac-group <name | !name>
set firewall ipv4 forward filter rule <1-999999> destination group mac-group <name | !name>
set firewall ipv4 input filter rule <1-999999> destination group mac-group <name | !name>
set firewall ipv4 output filter rule <1-999999> destination group mac-group <name | !name>
set firewall ipv4 name <name> rule <1-999999> destination group mac-group <name | !name>

Use a specific mac-group. Prepend character ! for inverted matching criteria.

set firewall ipv4 forward filter rule <1-999999> dscp [0-63 | start-end]
set firewall ipv4 input filter rule <1-999999> dscp [0-63 | start-end]
set firewall ipv4 output filter rule <1-999999> dscp [0-63 | start-end]
set firewall ipv4 name <name> rule <1-999999> dscp [0-63 | start-end]
set firewall ipv4 forward filter rule <1-999999> dscp-exclude [0-63 | start-end]
set firewall ipv4 input filter rule <1-999999> dscp-exclude [0-63 | start-end]
set firewall ipv4 output filter rule <1-999999> dscp-exclude [0-63 | start-end]
set firewall ipv4 name <name> rule <1-999999> dscp-exclude [0-63 | start-end]

Match based on dscp value.

set firewall ipv4 forward filter rule <1-999999> fragment [match-frag | match-non-frag]
set firewall ipv4 input filter rule <1-999999> fragment [match-frag | match-non-frag]
set firewall ipv4 output filter rule <1-999999> fragment [match-frag | match-non-frag]
set firewall ipv4 name <name> rule <1-999999> fragment [match-frag | match-non-frag]

Match based on fragment criteria.

set firewall ipv4 forward filter rule <1-999999> icmp [code | type] <0-255>
set firewall ipv4 input filter rule <1-999999> icmp [code | type] <0-255>
set firewall ipv4 output filter rule <1-999999> icmp [code | type] <0-255>
set firewall ipv4 name <name> rule <1-999999> icmp [code | type] <0-255>

Match based on icmp code and type.

set firewall ipv4 forward filter rule <1-999999> icmp type-name <text>
set firewall ipv4 input filter rule <1-999999> icmp type-name <text>
set firewall ipv4 output filter rule <1-999999> icmp type-name <text>
set firewall ipv4 name <name> rule <1-999999> icmp type-name <text>

Match based on icmp type-name criteria. Use tab for information about what type-name criteria are supported.

set firewall ipv4 forward filter rule <1-999999> inbound-interface name <iface>
set firewall ipv4 input filter rule <1-999999> inbound-interface name <iface>
set firewall ipv4 name <name> rule <1-999999> inbound-interface name <iface>

Match based on inbound interface. Wildcard * can be used. For example: eth2*. Prepending character ! for inverted matching criteria is also supported. For example !eth2

Note

If an interface is attached to a non-default vrf, when using inbound-interface, vrf name must be used. For example set firewall ipv4 forward filter rule 10 inbound-interface name MGMT

set firewall ipv4 forward filter rule <1-999999> inbound-interface group <iface_group>
set firewall ipv4 input filter rule <1-999999> inbound-interface group <iface_group>
set firewall ipv4 name <name> rule <1-999999> inbound-interface group <iface_group>

Match based on inbound interface group. Prepending character ! for inverted matching criteria is also supported. For example !IFACE_GROUP

set firewall ipv4 forward filter rule <1-999999> outbound-interface name <iface>
set firewall ipv4 output filter rule <1-999999> outbound-interface name <iface>
set firewall ipv4 name <name> rule <1-999999> outbound-interface name <iface>

Match based on outbound interface. Wildcard * can be used. For example: eth2*. Prepending character ! for inverted matching criteria is also supported. For example !eth2

Note

If an interface is attached to a non-default vrf, when using outbound-interface, real interface name must be used. For example set firewall ipv4 forward filter rule 10 outbound-interface name eth0

set firewall ipv4 forward filter rule <1-999999> outbound-interface group <iface_group>
set firewall ipv4 output filter rule <1-999999> outbound-interface group <iface_group>
set firewall ipv4 name <name> rule <1-999999> outbound-interface group <iface_group>

Match based on outbound interface group. Prepending character ! for inverted matching criteria is also supported. For example !IFACE_GROUP

set firewall ipv4 forward filter rule <1-999999> ipsec [match-ipsec | match-none]
set firewall ipv4 input filter rule <1-999999> ipsec [match-ipsec | match-none]
set firewall ipv4 output filter rule <1-999999> ipsec [match-ipsec | match-none]
set firewall ipv4 name <name> rule <1-999999> ipsec [match-ipsec | match-none]

Match based on ipsec criteria.

set firewall ipv4 forward filter rule <1-999999> limit burst <0-4294967295>
set firewall ipv4 input filter rule <1-999999> limit burst <0-4294967295>
set firewall ipv4 output filter rule <1-999999> limit burst <0-4294967295>
set firewall ipv4 name <name> rule <1-999999> limit burst <0-4294967295>

Match based on the maximum number of packets to allow in excess of rate.

set firewall ipv4 forward filter rule <1-999999> limit rate <text>
set firewall ipv4 input filter rule <1-999999> limit rate <text>
set firewall ipv4 output filter rule <1-999999> limit rate <text>
set firewall ipv4 name <name> rule <1-999999> limit rate <text>

Match based on the maximum average rate, specified as integer/unit. For example 5/minutes

set firewall ipv4 forward filter rule <1-999999> packet-length <text>
set firewall ipv4 input filter rule <1-999999> packet-length <text>
set firewall ipv4 output filter rule <1-999999> packet-length <text>
set firewall ipv4 name <name> rule <1-999999> packet-length <text>
set firewall ipv4 forward filter rule <1-999999> packet-length-exclude <text>
set firewall ipv4 input filter rule <1-999999> packet-length-exclude <text>
set firewall ipv4 output filter rule <1-999999> packet-length-exclude <text>
set firewall ipv4 name <name> rule <1-999999> packet-length-exclude <text>

Match based on packet length criteria. Multiple values from 1 to 65535 and ranges are supported.

set firewall ipv4 forward filter rule <1-999999> packet-type [broadcast | host | multicast | other]
set firewall ipv4 input filter rule <1-999999> packet-type [broadcast | host | multicast | other]
set firewall ipv4 output filter rule <1-999999> packet-type [broadcast | host | multicast | other]
set firewall ipv4 name <name> rule <1-999999> packet-type [broadcast | host | multicast | other]

Match based on packet type criteria.

set firewall ipv4 forward filter rule <1-999999> protocol [<text> | <0-255> | all | tcp_udp]
set firewall ipv4 input filter rule <1-999999> protocol [<text> | <0-255> | all | tcp_udp]
set firewall ipv4 output filter rule <1-999999> protocol [<text> | <0-255> | all | tcp_udp]
set firewall ipv4 name <name> rule <1-999999> protocol [<text> | <0-255> | all | tcp_udp]

Match a protocol criteria. A protocol number or a name which is here defined: /etc/protocols. Special names are all for all protocols and tcp_udp for tcp and udp based packets. The ! negate the selected protocol.

set firewall ipv4 forward fitler rule 10 protocol tcp_udp
set firewall ipv4 forward fitler rule 11 protocol !tcp_udp
set firewall ipv4 forward filter rule <1-999999> recent count <1-255>
set firewall ipv4 input filter rule <1-999999> recent count <1-255>
set firewall ipv4 output filter rule <1-999999> recent count <1-255>
set firewall ipv4 name <name> rule <1-999999> recent count <1-255>
set firewall ipv4 forward filter rule <1-999999> recent time [second | minute | hour]
set firewall ipv4 input filter rule <1-999999> recent time [second | minute | hour]
set firewall ipv4 output filter rule <1-999999> recent time [second | minute | hour]
set firewall ipv4 name <name> rule <1-999999> recent time [second | minute | hour]

Match bases on recently seen sources.

set firewall ipv4 forward filter rule <1-999999> tcp flags [not] <text>
set firewall ipv4 input filter rule <1-999999> tcp flags [not] <text>
set firewall ipv4 output filter rule <1-999999> tcp flags [not] <text>
set firewall ipv4 name <name> rule <1-999999> tcp flags [not] <text>

Allowed values fpr TCP flags: ack, cwr, ecn, fin, psh, rst, syn and urg. Multiple values are supported, and for inverted selection use not, as shown in the example.

set firewall ipv4 input filter rule 10 tcp flags 'ack'
set firewall ipv4 input filter rule 12 tcp flags 'syn'
set firewall ipv4 input filter rule 13 tcp flags not 'fin'
set firewall ipv4 forward filter rule <1-999999> state [established | invalid | new | related]
set firewall ipv4 input filter rule <1-999999> state [established | invalid | new | related]
set firewall ipv4 output filter rule <1-999999> state [established | invalid | new | related]
set firewall ipv4 name <name> rule <1-999999> state [established | invalid | new | related]

Match against the state of a packet.

set firewall ipv4 forward filter rule <1-999999> time startdate <text>
set firewall ipv4 input filter rule <1-999999> time startdate <text>
set firewall ipv4 output filter rule <1-999999> time startdate <text>
set firewall ipv4 name <name> rule <1-999999> time startdate <text>
set firewall ipv4 forward filter rule <1-999999> time starttime <text>
set firewall ipv4 input filter rule <1-999999> time starttime <text>
set firewall ipv4 output filter rule <1-999999> time starttime <text>
set firewall ipv4 name <name> rule <1-999999> time starttime <text>
set firewall ipv4 forward filter rule <1-999999> time stopdate <text>
set firewall ipv4 input filter rule <1-999999> time stopdate <text>
set firewall ipv4 output filter rule <1-999999> time stopdate <text>
set firewall ipv4 name <name> rule <1-999999> time stopdate <text>
set firewall ipv4 forward filter rule <1-999999> time stoptime <text>
set firewall ipv4 input filter rule <1-999999> time stoptime <text>
set firewall ipv4 output filter rule <1-999999> time stoptime <text>
set firewall ipv4 name <name> rule <1-999999> time stoptime <text>
set firewall ipv4 forward filter rule <1-999999> time weekdays <text>
set firewall ipv4 input filter rule <1-999999> time weekdays <text>
set firewall ipv4 output filter rule <1-999999> time weekdays <text>
set firewall ipv4 name <name> rule <1-999999> time weekdays <text>

Time to match the defined rule.

set firewall ipv4 forward filter rule <1-999999> ttl <eq | gt | lt> <0-255>
set firewall ipv4 input filter rule <1-999999> ttl <eq | gt | lt> <0-255>
set firewall ipv4 output filter rule <1-999999> ttl <eq | gt | lt> <0-255>
set firewall ipv4 name <name> rule <1-999999> ttl <eq | gt | lt> <0-255>

Match time to live parameter, where ‘eq’ stands for ‘equal’; ‘gt’ stands for ‘greater than’, and ‘lt’ stands for ‘less than’.

set firewall ipv4 forward filter rule <1-999999> recent count <1-255>
set firewall ipv4 input filter rule <1-999999> recent count <1-255>
set firewall ipv4 output filter rule <1-999999> recent count <1-255>
set firewall ipv4 name <name> rule <1-999999> recent count <1-255>
set firewall ipv4 forward filter rule <1-999999> recent time <second | minute | hour>
set firewall ipv4 input filter rule <1-999999> recent time <second | minute | hour>
set firewall ipv4 output filter rule <1-999999> recent time <second | minute | hour>
set firewall ipv4 name <name> rule <1-999999> recent time <second | minute | hour>

Match when ‘count’ amount of connections are seen within ‘time’. These matching criteria can be used to block brute-force attempts.

Synproxy

Synproxy connections

set firewall ipv4 [input | forward] filter rule <1-999999> action synproxy
set firewall ipv4 [input | forward] filter rule <1-999999> protocol tcp
set firewall ipv4 [input | forward] filter rule <1-999999> synproxy tcp mss <501-65535>

Set TCP-MSS (maximum segment size) for the connection

set firewall ipv4 [input | forward] filter rule <1-999999> synproxy tcp window-scale <1-14>

Set the window scale factor for TCP window scaling

Example synproxy

Requirements to enable synproxy:

  • Traffic must be symmetric

  • Synproxy relies on syncookies and TCP timestamps, ensure these are enabled

  • Disable conntrack loose track option

set system sysctl parameter net.ipv4.tcp_timestamps value '1'

set system conntrack tcp loose disable
set system conntrack ignore ipv4 rule 10 destination port '8080'
set system conntrack ignore ipv4 rule 10 protocol 'tcp'
set system conntrack ignore ipv4 rule 10 tcp flags syn

set firewall global-options syn-cookies 'enable'
set firewall ipv4 input filter rule 10 action 'synproxy'
set firewall ipv4 input filter rule 10 destination port '8080'
set firewall ipv4 input filter rule 10 inbound-interface name 'eth1'
set firewall ipv4 input filter rule 10 protocol 'tcp'
set firewall ipv4 input filter rule 10 synproxy tcp mss '1460'
set firewall ipv4 input filter rule 10 synproxy tcp window-scale '7'
set firewall ipv4 input filter rule 1000 action 'drop'
set firewall ipv4 input filter rule 1000 state invalid

Operation-mode Firewall

Rule-set overview

show firewall

This will show you a basic firewall overview, for all ruleset, and not only for ipv4

vyos@vyos:~$ show firewall
Rulesets Information

---------------------------------
ipv4 Firewall "forward filter"

Rule     Action    Protocol      Packets    Bytes  Conditions
-------  --------  ----------  ---------  -------  -----------------------------
20       accept    all                 0        0  ip saddr @N_TRUSTEDv4  accept
21       jump      all                 0        0  jump NAME_AUX
default  accept    all                 0        0

---------------------------------
ipv4 Firewall "input filter"

Rule     Action    Protocol      Packets    Bytes  Conditions
-------  --------  ----------  ---------  -------  -------------------------
10       accept    all               156    14377  iifname != @I_LAN  accept
default  accept    all                 0        0

---------------------------------
ipv4 Firewall "name AUX"

  Rule  Action    Protocol      Packets    Bytes  Conditions
------  --------  ----------  ---------  -------  --------------------------------------------
    10  accept    icmp                0        0  meta l4proto icmp  accept
    20  accept    udp                 0        0  meta l4proto udp ip saddr @A_SERVERS  accept
    30  drop      all                 0        0  ip saddr != @A_SERVERS iifname "eth2"

---------------------------------
ipv4 Firewall "output filter"

Rule     Action    Protocol      Packets    Bytes  Conditions
-------  --------  ----------  ---------  -------  ----------------------------------------
10       reject    all                 0        0  oifname @I_LAN
20       accept    icmp                2      168  meta l4proto icmp oifname "eth0"  accept
default  accept    all                72     9258

---------------------------------
ipv6 Firewall "input filter"

Rule     Action    Protocol      Packets    Bytes  Conditions
-------  --------  ----------  ---------  -------  -------------------------------
10       accept    all                 0        0  ip6 saddr @N6_TRUSTEDv6  accept
default  accept    all                 2      112

vyos@vyos:~$
show firewall summary

This will show you a summary of rule-sets and groups

vyos@vyos:~$ show firewall summary
Ruleset Summary

IPv6 Ruleset:

Ruleset Hook    Ruleset Priority      Description
--------------  --------------------  -------------------------
forward         filter
input           filter
ipv6_name       IPV6-VyOS_MANAGEMENT
ipv6_name       IPV6-WAN_IN           PUBLIC_INTERNET

IPv4 Ruleset:

Ruleset Hook    Ruleset Priority    Description
--------------  ------------------  -------------------------
forward         filter
input           filter
name            VyOS_MANAGEMENT
name            WAN_IN              PUBLIC_INTERNET

Firewall Groups

Name                     Type                References               Members
-----------------------  ------------------  -----------------------  ----------------
PBX                      address_group       WAN_IN-100               198.51.100.77
SERVERS                  address_group       WAN_IN-110               192.0.2.10
                                             WAN_IN-111               192.0.2.11
                                             WAN_IN-112               192.0.2.12
                                             WAN_IN-120
                                             WAN_IN-121
                                             WAN_IN-122
SUPPORT                  address_group       VyOS_MANAGEMENT-20       192.168.1.2
                                             WAN_IN-20
PHONE_VPN_SERVERS        address_group       WAN_IN-160               10.6.32.2
PINGABLE_ADRESSES        address_group       WAN_IN-170               192.168.5.2
                                             WAN_IN-171
PBX                      ipv6_address_group  IPV6-WAN_IN-100          2001:db8::1
SERVERS                  ipv6_address_group  IPV6-WAN_IN-110          2001:db8::2
                                             IPV6-WAN_IN-111          2001:db8::3
                                             IPV6-WAN_IN-112          2001:db8::4
                                             IPV6-WAN_IN-120
                                             IPV6-WAN_IN-121
                                             IPV6-WAN_IN-122
SUPPORT                  ipv6_address_group  IPV6-VyOS_MANAGEMENT-20  2001:db8::5
                                             IPV6-WAN_IN-20
show firewall ipv4 [forward | input | output] filter
show firewall ipv4 name <name>

This command will give an overview of a single rule-set.

vyos@vyos:~$ show firewall ipv4 input filter
Ruleset Information

---------------------------------
IPv4 Firewall "input filter"

Rule     Action    Protocol      Packets    Bytes  Conditions
-------  --------  ----------  ---------  -------  -----------------------------------------
5        jump      all                 0        0  iifname "eth2"  jump NAME_VyOS_MANAGEMENT
default  accept    all
show firewall ipv4 [forward | input | output] filter rule <1-999999>
show firewall ipv4 name <name> rule <1-999999>

This command will give an overview of a rule in a single rule-set, plus information for default action.

vyos@vyos:~$show firewall ipv4 output filter rule 20
Rule Information

---------------------------------
ipv4 Firewall "output filter"

Rule     Action    Protocol      Packets    Bytes  Conditions
-------  --------  ----------  ---------  -------  ----------------------------------------
20       accept    icmp                2      168  meta l4proto icmp oifname "eth0"  accept
default  accept    all               286    47614

vyos@vyos:~$
show firewall statistics

This will show you a statistic of all rule-sets since the last boot.

Show Firewall log

show log firewall
show log firewall ipv4
show log firewall ipv4 [forward | input | output | name]
show log firewall ipv4 [forward | input | output] filter
show log firewall ipv4 name <name>
show log firewall ipv4 [forward | input | output] filter rule <rule>
show log firewall ipv4 name <name> rule <rule>

Show the logs of all firewall; show all ipv4 firewall logs; show all logs for particular hook; show all logs for particular hook and priority; show all logs for particular custom chain; show logs for specific Rule-Set.

Example Partial Config

firewall {
    group {
        network-group BAD-NETWORKS {
            network 198.51.100.0/24
            network 203.0.113.0/24
        }
        network-group GOOD-NETWORKS {
            network 192.0.2.0/24
        }
        port-group BAD-PORTS {
            port 65535
        }
    }
    ipv4 {
        forward {
            filter {
                default-action accept
                rule 5 {
                    action accept
                    source {
                        group {
                            network-group GOOD-NETWORKS
                        }
                    }
                }
                rule 10 {
                    action drop
                    description "Bad Networks"
                    protocol all
                    source {
                        group {
                            network-group BAD-NETWORKS
                        }
                    }
                }
            }
        }
    }
}

Update geoip database

update geoip

Command used to update GeoIP database and firewall sets.