Subject: CARP Patch
To: None <,>
From: Liam J. Foy <>
List: tech-net
Date: 03/01/2006 09:47:28
Hello all,

I'm pleased to announce the availability of CARP on NetBSD. The following
patch is the first patch release. CARP is:

" CARP is a tool to help achieve system redundancy, by having multiple
computers creating a single, virtual network interface between them, so
that if any machine fails, another can respond instead, and/or allowing
a degree of load sharing between systems. "

For further indepth information on CARP, please view the OpenBSD FAQ by
the following URL:

Over the last few months I've been working on integrating it with NetBSD
and am finally happy to release the patch. While here, I'd like to
express my deepest gratitude to Joerg Sonnenberger and Jeff Rizzo for
debugging and testing assistance. You can view the NetBSD patch at:
	(Kindly hosted by joerg)

This patch was created from yesterday's HEAD. I've been doing extensive
testing using HEAD from a week ago. I don't think there are any major
changes which should affect it. I've only give it a few running tests on
yesterdays HEAD and I've had no problems.

CARP is working along side both OpenBSD and FreeBSD soundly. I'd
really like more indepth testing on multiple machines. Currently I have
tested it extensively with two machines (NetBSD HEAD and FreeBSD).
Everything seems to be working just like it should.

This patch has been released in parallel to the on going discussion
about the legal issues surrounding CARP. More information can be seen

Here is a quick example to get CARP working once the patch has been
applied and compiled:

	(Add 'pseudo-device carp' to kernel and re-build)

	machine1# ifconfig carp0 create
	machine1# ifconfig carp0 vhid 1 pass netcarpy

	machine2# ifconfig carp0 create
	machine2# ifconfig carp0 vhid 1 pass netcarpy

There are also some sysctls which are explained in the man page.

If any problems are found, please report them on

		Liam J. Foy