vrrpd is an implementation of VRRPv2 as specified in rfc2338. It run
in userspace for linux.
In short, VRRP is a protocol which elects a master server on a LAN and
the master answers to a 'virtual ip address'. If it fails, a backup
server takes over the ip address.
A longer answer in the rfc2338 abstract :
"This memo defines the Virtual Router Redundancy Protocol (VRRP).
VRRP specifies an election protocol that dynamically assigns
responsibility for a virtual router to one of the VRRP routers on a
LAN. The VRRP router controlling the IP address(es) associated with
a virtual router is called the Master, and forwards packets sent to
these IP addresses. The election process provides dynamic fail over
in the forwarding responsibility should the Master become
unavailable. This allows any of the virtual router IP addresses on
the LAN to be used as the default first hop router by end-hosts. The
advantage gained from using VRRP is a higher availability default
path without requiring configuration of dynamic routing or router
discovery protocols on every end-host."
Copyright (C) The Internet Society (1998). All Rights Reserved.
Monitored interface functionality is useful on high availability
router or firewall platforms, where single interface failure
can cause asymmetrical routing issues.
Ideally, what is required is a method for a vrrpd process to
detect a failure of the 'other' network interface, and lower
it's own VRRP priority below that of the 'backup' vrrpd process.
This allows failover to occur normally.
display this short inlined help
Don't handle the virtual mac address
Go into background mode, daemonize
the interface name to run on. More than one interface can be monitored
by the one vrrpd process, a list like "eth1 eth2 eth3 eth4 eth5"
is acceptable. Losing link-beat on any of these will cause
the priority of that vrrpd process to be decreased by the specified
value, or a default of 100.
Note that as MII calls are used, this implementation is limited to
Fast and Gigabit Ethernet chipsets only - 10Mbps Ethernet cards
will not work.
the id of the virtual server [1-255]
iqxSwitch the preemption mode (Enabled by default)
set the authentification type
Password is a symbolic security, anybody with a sniffer can break it.
AH is a bit stronger.
Set the priority of this host in the virtual server (dfl: 100)
specify the directory where the pid file is stored (dfl: /var/run)
Set the advertisement interval (in sec) (dfl: 1)
Interface(s) to monitor for failure. Use " " for multiple interfaces
Set the delta to decrease priority by (dfl: 50)
the ip address(es) of the virtual server
vrrpd -i eth0 -v 50 10.0.0.1
run vrrp on the interface eth0 with the virtual id 50 and 10.0.0.1 as virtual