Date: Fri, 18 Oct 2013 10:22:50 +0000 From: Ole Myhre <ole.myhre@dataoppdrag.no> To: "freebsd-net@freebsd.org" <freebsd-net@freebsd.org> Subject: Interface up/down, carp and loopback route Message-ID: <C5A69C67E0D032469281F68C7CFD6AA009E03B5E@EX-MBX01.cust-d1.dataoppdrag.no>
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Hi,
I'm seeing some inconsistent behavior with how carp handles the loopback ro=
ute when it transition from MASTER to BACKUP and how the loopback route is =
handled when an interface is marked down.
This is currently tested on 10.0-BETA1.
(fw1 and fw2 has just been booted)
[root@fw1 ~]# ifconfig em2 | grep 'carp\|inet '
inet 192.168.0.1 netmask 0xffffff00 broadcast 192.168.0.255 vhid 1
carp: MASTER vhid 1 advbase 1 advskew 0
[root@fw1 ~]# netstat -rn | grep 192.168.0.1
192.168.0.1 link#3 UHS 0 0 lo0
[root@fw1 ~]#=20
[root@fw2 ~]# ifconfig em2 | grep 'carp\|inet '
inet 192.168.0.1 netmask 0xffffff00 broadcast 192.168.0.255 vhid 1
carp: BACKUP vhid 1 advbase 1 advskew 0
[root@fw2 ~]# netstat -rn | grep 192.168.0.1
[root@fw2 ~]#
[root@fw1 ~]# ifconfig em2 vhid 1 advskew 100
[root@fw1 ~]# ifconfig em2 | grep 'carp\|inet '
inet 192.168.0.1 netmask 0xffffff00 broadcast 192.168.0.255 vhid 1
carp: BACKUP vhid 1 advbase 1 advskew 100
[root@fw1 ~]# netstat -rn | grep 192.168.0.1
[root@fw1 ~]#
[root@fw2 ~]# ifconfig em2 | grep 'carp\|inet '
inet 192.168.0.1 netmask 0xffffff00 broadcast 192.168.0.255 vhid 1
carp: MASTER vhid 1 advbase 1 advskew 0
[root@fw2 ~]# netstat -rn | grep 192.168.0.1
192.168.0.1 link#3 UHS 0 0 lo0
[root@fw2 ~]#
[root@fw2 ~]# ifconfig em2 vhid 1 advskew 200
[root@fw2 ~]# ifconfig em2 | grep 'carp\|inet '
inet 192.168.0.1 netmask 0xffffff00 broadcast 192.168.0.255 vhid 1
carp: BACKUP vhid 1 advbase 1 advskew 200
[root@fw2 ~]# netstat -rn | grep 192.168.0.1
[root@fw2 ~]#
So far, so good. The loopback route is removed when the carp interface goes=
back to BACKUP, and added when it goes to MASTER.
However, if I mark an interface as down:
[root@fw1 ~]# ifconfig em2 | grep 'carp\|inet '
inet 192.168.0.1 netmask 0xffffff00 broadcast 192.168.0.255 vhid 1
carp: MASTER vhid 1 advbase 1 advskew 100
[root@fw1 ~]# netstat -rn | grep 192.168.0.1
192.168.0.1 link#3 UHS 0 0 lo0
[root@fw1 ~]# ifconfig em2 down
[root@fw1 ~]# ifconfig em2 | grep 'carp\|inet '
inet 192.168.0.1 netmask 0xffffff00 broadcast 192.168.0.255 vhid 1
carp: INIT vhid 1 advbase 1 advskew 100
[root@fw1 ~]# netstat -rn | grep 192.168.0.1
192.168.0.1 link#3 UHS 0 0 lo0
[root@fw1 ~]#
The loopback route is not removed.
The same things happen if I set any interface to down, not just interfaces =
with carp enabled.
Is this expected behavior, or is it a bug? Or maybe it is (or should be) a =
sysctl setting? And is the loopback route really necessary at all?
--=20
Ole Myhre
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