Common Address Redundancy Protocol (CARP) integrated
Liam J. Foy has committed his work on the
Common Address Redundancy Protocol (CARP) to NetBSD-current.
To quote from his mail,
``CARP is the Common Address Redundancy Protocol. Its primary purpose
is to allow multiple hosts on the same network segment to share an IP
address. CARP is a secure, free alternative to the Virtual Router
Redundancy Protocol and the Hot Standby Router Protocol.
CARP works by allowing a group of hosts on the same network segment to
share an IP address. This group of hosts is referred to as a
"redundancy group". The redundancy group is assigned an IP Address
that is shared amongst the group members. Within the group, one host
is designated the "master" and the rest as "backups". The master host
is the one that currently "holds" the shared IP; it responds to any
traffic or ARP requests directed towards it. Each host may belong
to more than one redundancy group at a time.
One common use for CARP is to create a group of redundant firewalls.
The virtual IP that is assigned to the redundancy group is configured on
client machines as the default gateway. In the event that the master
firewall suffers a failure or is taken offline, the IP will move
to one of the backups firewalls and the service will continue
CARP supports IPv4 and IPv6.''
for a lot more information on how to enable CARP and