Re: [Vserver] ifconfig problem with virtual interfaces

From: Michael S. Zick <>
Date: Mon 23 Jan 2006 - 13:06:16 GMT
Message-Id: <>

On Mon January 23 2006 05:31, Raimund Specht wrote:
> Hi !
> We have a very strange problem here with virtual IP addresses (various
> up-to-date 2.6 kernels with vserver 2.0):
> Let eth0 have a normal IP address. Let v1 and v2 be two vservers with a
> virtual IP on eth0 each.
> # vserver v1 start
> # vserver v2 start
> ifconfig shows eth0, eth0:v1, and eth0:v2 as expected, everything works.
> # vserver v1 stop
> Now ifconfig shows that all virtual IPs have been removed although
> vserver-stat shows that v2 is still running. Networking with v2 doesn't
> work either. This only happens if the vserver, that was startet first, ist
> stopped. Other orderings work fine.
> This problem is not vserver related, we can reproduce it on non-vserver
> systems/kernels too. The following commands reproduce it on 90% of our
> systems (Debian, Ubuntu, Gentoo, all with Linux 2.6):
> # ifconfig eth0:1
> # ifconfig eth0:2
> # ifconfig eth0:1 del
> Does anyone else have this problem?
> Any workaround except defining an eth0:dummy interface outside any vserver?
Stolen from the Linux-VServer mailing list:

and recent kernels (means 2.6.14 and later) support
an actual workaround for this 'feature', which can
be easily activated via sysctl

?sysctl -w net.ipv4.conf.all.promote_secondaries=1

this will activate the so called secondary promotion
which means that the kernel will 'elect' a secondary
to become the new primary if the old one is taken
down ...

Say thank you Herbert.

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Received on Mon Jan 23 13:06:44 2006

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