dhclient started on a bridge tries to assign addresses to all bridged devices

[Thomas Schweikle]

Network setup:

manual eth0
iface eth0 inet manual
  pre-up ifconfig $IFACE 0.0.0.0 promisc up
  ...

auto br0
iface br0 inet manual
  pre-up ifup eth0
  pre-up brctl addbr $IFACE
  pre-up brctl addif $IFACE eth0
  pre-up dhclient $IFACE
  ...

after the bridge is up, dhclient assigns addresses to both devices: vb0 and eth0.
This breaks nearly everything: two (or more) interfaces sharing the same IP-address, two (or more) default routes on the same network. Networking will not work any more in this case. After you remove the various device addresses, leaving only one for the bridge the network ist back up and running again.

dhclient should only assign the given interface an address!

I found this bug with maveric and lucid.

ProblemType: Bug
DistroRelease: Ubuntu 10.04
Package: dhcp3-client 3.1.3-2ubuntu3 [modified: sbin/dhclient3]
ProcVersionSignature: Ubuntu 2.6.32-25.45-generic-pae 2.6.32.21+drm33.7
Uname: Linux 2.6.32-25-generic-pae i686
Architecture: i386
Date: Thu Nov 18 20:12:22 2010
InstallationMedia: Ubuntu-Server 10.04 LTS "Lucid Lynx" - Release i386 (20100427)
ProcCmdLine: BOOT_IMAGE=/boot/vmlinuz-2.6.32-25-generic-pae root=UUID=c90d9260-a7c9-4b68-a903-d6d38ed1e4a6 ro
ProcEnviron:
 LC_CTYPE=en_US.UTF-8
 SHELL=/bin/zsh
SourcePackage: dhcp3

[Thomas Schweikle (tps)]

dhclient-versions between maverick and lucid match --- looks as if it is the very same bug!