firehol-interface man page

firehol-interface — interface definition


{ interface | interface46 } real-interface name rule-params

interface4 real-interface name rule-params

interface6 real-interface name rule-params


An interface definition creates a firewall for protecting the host on which the firewall is running.

The default policy is DROP, so that if no subcommands are given, the firewall will just drop all incoming and outgoing traffic using this interface.

The behaviour of the defined interface is controlled by adding subcommands from those listed in Interface Subcommands.


Forwarded traffic is never matched by the interface rules, even if it was originally destined for the firewall but was redirected using NAT. Any traffic to be passed through the firewall for whatever reason must be in a router (see firehol-router(5)).


Writing interface4 is equivalent to writing ipv4 interface and ensures the defined interface is created only in the IPv4 firewall along with any rules within it.

Writing interface6 is equivalent to writing ipv6 interface and ensures the defined interface is created only in the IPv6 firewall along with any rules within it.

Writing interface46 is equivalent to writing both interface and ensures the defined interface is created in both the IPv4 and IPv6 firewalls. Any rules within it will also be applied to both, unless they specify otherwise.



This is the interface name as shown by ip link show. Generally anything iptables(8) accepts is valid.

The + (plus sign) after some text will match all interfaces that start with this text.

Multiple interfaces may be specified by enclosing them within quotes, delimited by spaces for example:

interface "eth0 eth1 ppp0" myname

This is a name for this interface. You should use short names (10 characters maximum) without spaces or other symbols.

A name should be unique for all FireHOL interface and router definitions.


The set of rule parameters to further restrict the traffic that is matched to this interface.

See firehol-params(5) for information on the parameters that can be used. Some examples:

interface eth0 intranet src

interface eth0 internet src not "${UNROUTABLE_IPS}"

See firehol.conf(5) for an explanation of ${UNROUTABLE_IPS}.

See Also

firehol(1) - FireHOL program
firehol.conf(5) - FireHOL configuration
firehol-params(5) - optional rule parameters
firehol-modifiers(5) - ipv4/ipv6 selection
firehol-router(5) - router definition
firehol-iptables(5) - iptables helper
firehol-masquerade(5) - masquerade helper
FireHOL Website (http://firehol.org/)
FireHOL Online PDF Manual (http://firehol.org/firehol-manual.pdf)
FireHOL Online HTML Manual (http://firehol.org/manual)

Interface Subcommands

firehol-policy(5) - policy command
firehol-protection(5) - protection command
firehol-server(5) - server, route commands
firehol-client(5) - client command
firehol-group(5) - group command


FireHOL Team.

Referenced By

firehol-actions(5), firehol-client(5), firehol-conf(5), firehol-group(5), firehol-masquerade(5), firehol-modifiers(5), firehol-nat(5), firehol-params(5), firehol-policy(5), firehol-protection(5), firehol-proxy(5), firehol-router(5), firehol-server(5), firehol-tcpmss(5).

Explore man page connections for firehol-interface(5).

firehol-interface4(5), firehol-interface46(5) and firehol-interface6(5) are aliases of firehol-interface(5).

Built 2.0.1 15 Feb 2015