Projects / UCARP


UCARP allows a pair of hosts to share common virtual IP addresses in order to provide automatic failover. It is a portable userland implementation of the secure and patent- free Common Address Redundancy Protocol (CARP, OpenBSD's alternative to VRRP). Strong points of the CARP protocol include its very low overhead, cryptographically signed messages, interoperability between different operating systems and no need for any dedicated extra network link between redundant hosts.

Operating Systems

Recent releases

  •  27 May 2009 22:33

    Release Notes: UCARP can now send advertisements as broadcasts instead of multicasts.

    •  05 Aug 2008 00:26

      Release Notes: Breakage introduced with version 1.4 should finally be fixed. Selection of the master has been improved. An option has been added to bypass network cable plugin detection for NICs that don't have that feature.

      •  21 Jan 2008 15:44

        Release Notes: This version should finally fix every issue people had with gratuitous ARP announcements. Nodes configured with the same intervals shouln't flip-flop any more. This is a recommended upgrade for everyone.

        •  04 Jul 2007 18:02

          Release Notes: All known bugs from 1.2 should be fixed. Gratuitous ARP packets should now be properly recognized by most ethernet switches. New options have been added in order to read the secret key from a file and in order to add arguments (like the virtual IP address) to up/down scripts.

          •  20 Feb 2006 15:32

            Release Notes: Minor bugs were fixed. The program's own multicast packets are now ignored. A new "neutral" mode has been implemented.


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