NAME

       ifupdown-multi-interfaces - ifupdown-multi extension for the interfaces(5) file format

DESCRIPTION

       /etc/network/interfaces  contains  network  interface information for the ifup(8) and ifdown(8) commands.
       This manpage describes the ifupdown-multi extensions to the the standard interfaces(5) file format.

       The ifupdown-multi extensions to ifupdown integrate Linux's policy routing  based  support  for  multiple
       default  gateways on independent network connections. These extensions can replace a typical shell script
       based approach that directly invokes a sequence of ip(8) commands for configuring multiple  uplinks  with
       declarative syntax in the /etc/network/interfaces file.

       ifupdown-multi records the policy information used to bring up each network interface when ifup(8) is run
       and removes the same policy routing information when ifdown(8) is run.

IFACE OPTIONS

       The  standard  address and netmask options must be set for each interface. The gateway option must NOT be
       set.

       The  new  multi_gateway  and  multi_table  options  must  be  set  to  configure  policy   routing   with
       ifupdown-multi.

       Additionally,  the multi_gateway_weight and multi_preferred_prefixes options can be specified in order to
       control optional policy routing features.

       multi_gateway address
              Default gateway for this interface. (Required.)

       multi_table id
              Table identifier. This must be a numeric value, and each  interface  must  have  a  unique  value.
              Recommended range: 1-1000. (Required.)

       multi_gateway_weight weight
              Set  this  gateway's  weight. This value is directly passed as the weight parameter to the nexthop
              part of an ip-route(8) route object. Higher values indicate higher relative bandwidth or  quality.
              (Optional.)

       multi_preferred_prefixes prefix [prefix]...
              Prefer  this connection for the given prefixes. This option configures the routing policy database
              using the ip-rule(8) command to use this connection for the specified prefixes. (Optional.)

EXAMPLES

       The following example shows  a  basic  configuration  with  two  network  interfaces.   eth0  is  on  the
       198.51.100.0/24  network,  while  eth1  is  on  the  203.0.113.0/24  network. Each interface stanza has a
       "multi_gateway" option, as opposed to the usual "gateway" option. Each  interface  stanza  also  needs  a
       "multi_table" option, whose parameter is a small, unique non-negative integer.  (This number will be used
       internally to uniquely identify an interface-specific routing table.)

          auto eth0
          iface eth0 inet static
              address 198.51.100.123
              netmask 255.255.255.0
              multi_table 1
              multi_gateway 198.51.100.1

          auto eth1
          iface eth1 inet static
              address 203.0.113.234
              netmask 255.255.255.0
              multi_table 2
              multi_gateway 203.0.113.1

       The  following  example  shows  a  more complicated setup using optional ifupdown-multi parameters. It is
       similar to the first example, but the network connection on eth0 is preferred for most  connections,  and
       several network prefixes prefer to use one or the other network connection.

          auto eth0
          iface eth0 inet static
              address 198.51.100.123
              netmask 255.255.255.0
              multi_table 1
              multi_gateway 198.51.100.1
              multi_gateway_weight 5
              multi_preferred_prefixes 10.0.0.0/8

          auto eth1
          iface eth1 inet static
              address 203.0.113.234
              netmask 255.255.255.0
              multi_table 2
              multi_gateway 203.0.113.1
              multi_gateway_weight 1
              multi_preferred_prefixes 172.16.0.0/12 192.168.0.0/16

FILES

       /etc/network/interfaces
              System-wide network interface configuration. See interfaces(5).

       /run/network/ifupdown-multi.*
              State information used by ifupdown-multi.

SEE ALSO

       interfaces(5), ifup(8), ip(8), ip-route(8), ip-rule(8).

       Linux Advanced Routing & Traffic Control HOWTO -- Chapter 4: Rules.
              http://www.tldp.org/HOWTO/Adv-Routing-HOWTO/lartc.rpdb.html

0.1.0                                           17 September 2013                   IFUPDOWN-MULTI-INTERFACES(5)