NAME

ifdepd — Interface Dependancy daemon

SYNOPSIS

ifdepd [-v|q] [-d] -S src-if1[:src-if2...] -D dst-if1[:dst-if2...]

DESCRIPTION

The ifdepd daemon implements dependencies between network interfaces in a reliable way. If any of the source interfaces src-if1 ... src-ifn fails (hardware error, no carrier etc.), ifdepd sets all destination interfaces dst-if1 ... dst-ifn to state down. If all source interfaces src-if1 ... src-ifn are active, ifdepd sets all destination interfaces dst-if1 ... dst-ifn to state up. For example, it can be used with carp(4) to provide failover functionality on gateways/firewalls.

The following options are available:

-v: Verbose mode. The details of interface state transitions are displayed on the user's terminal or in syslog messages if running in daemon mode.
-q: Quiet mode. No messages are displayed.
-d: Daemon mode. Run in background and log to syslog.
-S src-if1[:src-if2...]: Specify source interface(s).
-D dst-if1[:dst-if2...]: Specify destination interface(s).

EXAMPLES

ifdepd -d -S em0:bge0 -D
  carp0:carp1

Example for building a high available firewall system with carp(4). The internal physical interface is em0 and the external physical interface is bge0, carp0 is the carp(4) interface for the internal physical interface em0 and carp1 is the carp(4) interface for the external physical interface bge0. If one of the physical interfaces em0 or bge0 fails, ifdepd sets both carp(4) interfaces carp0 and carp1 to down, which triggers a failover on the carp(4) layer.

HISTORY

The ifdepd program was written as an simple and reliable alternative for ifstated(8) to implement interface dependencies on redundant gateway/firewall systems which are using carp(4)

AUTHORS

"Alexander Hausner" ⟨alex@hugo.bmg.gv.at⟩