[Bug 677153] [NEW] dhclient assigns all interfaces connected to a bridge addresses

[Thomas Schweikle]

Public bug reported:

After the bridge is up, dhclient assigns all interfaces connected to the
bridge an IP address. This breaks networking: two (or more) default
routes, two (or more) interfaces assigned the same address. In some
cases: interfaces configured static are assigned dynamic addresses
(absolutely unwanted!). After cleaning up the mess, dhclient produced,
all is fine again --- until your leases expire ...

dhclient should only assign addresses to interfaces given on
commandline!

I found this bug with maverik and lucid (bug report #677152)

Network setup:
manual eth0
iface eth0 inet manual
  pre-up ifconfig eth0 0.0.0.0 promisc up
  ...

auto vb0
iface vb0 inet manual
  pre-up ifup eth0
  pre-up brctl addbr vb0
  pre-up brctl addif vb0 eth0
  pre-up dhclient vb0
  ...


root at ivory:~# dhclient3 -e IF_METRIC=100 -pf /var/run/dhclient.vb0.pid -lf /var/lib/dhcp3/dhclient.vb0.leases vb0
There is already a pid file /var/run/dhclient.vb0.pid with pid 1805
removed stale PID file
Internet Systems Consortium DHCP Client V3.1.3
Copyright 2004-2009 Internet Systems Consortium.
All rights reserved.
For info, please visit https://www.isc.org/software/dhcp/

Listening on LPF/eth0/00:1e:68:06:4b:e9
Sending on   LPF/eth0/00:1e:68:06:4b:e9
Listening on LPF/vb0/00:1e:68:06:4b:e9
Sending on   LPF/vb0/00:1e:68:06:4b:e9
Sending on   Socket/fallback
DHCPREQUEST of 192.168.1.113 on eth0 to 255.255.255.255 port 67
DHCPREQUEST of 192.168.1.113 on vb0 to 255.255.255.255 port 67
DHCPACK of 192.168.1.113 from 192.168.1.1
bound to 192.168.1.113 -- renewal in 1382 seconds.
root at ivory:~# route -n
Kernel-IP-Routentabelle
Ziel            Router          Genmask         Flags Metric Ref    Use Iface
172.16.38.0     0.0.0.0         255.255.255.0   U     0      0        0 vmnet8
192.168.1.0     0.0.0.0         255.255.255.0   U     0      0        0 eth0
192.168.1.0     0.0.0.0         255.255.255.0   U     0      0        0 vb0
172.16.31.0     0.0.0.0         255.255.255.0   U     0      0        0 vmnet1
0.0.0.0         192.168.1.1     0.0.0.0         UG    100    0        0 vb0
0.0.0.0         192.168.1.1     0.0.0.0         UG    100    0        0 eth0
root at ivory:~# ifconfig eth0
eth0      Link encap:Ethernet  Hardware Adresse 00:1e:68:06:4b:e9  
          inet Adresse:192.168.1.113  Bcast:192.168.1.255  Maske:255.255.255.0
          inet6-Adresse: fe80::21e:68ff:fe06:4be9/64 Gültigkeitsbereich:Verbindung
          UP BROADCAST RUNNING MULTICAST  MTU:1500  Metrik:1
          RX packets:7865272 errors:0 dropped:0 overruns:0 frame:0
          TX packets:4017664 errors:0 dropped:0 overruns:0 carrier:0
          Kollisionen:0 Sendewarteschlangenlänge:1000 
          RX bytes:11925842333 (11.9 GB)  TX bytes:287765516 (287.7 MB)
          Interrupt:18 

root at ivory:~# ifconfig vb0
vb0       Link encap:Ethernet  Hardware Adresse 00:1e:68:06:4b:e9  
          inet Adresse:192.168.1.113  Bcast:192.168.1.255  Maske:255.255.255.0
          inet6-Adresse: fe80::21e:68ff:fe06:4be9/64 Gültigkeitsbereich:Verbindung
          UP BROADCAST RUNNING MULTICAST  MTU:1500  Metrik:1
          RX packets:7841208 errors:0 dropped:0 overruns:0 frame:0
          TX packets:4018042 errors:0 dropped:0 overruns:0 carrier:0
          Kollisionen:0 Sendewarteschlangenlänge:0 
          RX bytes:11784284373 (11.7 GB)  TX bytes:271726107 (271.7 MB)

root at ivory:~# brctl show
bridge name     bridge id               STP enabled     interfaces
vb0             8000.001e68064be9       no              eth0

ProblemType: Bug
DistroRelease: Ubuntu 10.10
Package: dhcp3-client 3.1.3-2ubuntu6
ProcVersionSignature: Error: [Errno 2] No such file or directory: '/proc/version_signature'
Uname: Linux 2.6.35.8 x86_64
Architecture: amd64
Date: Thu Nov 18 20:12:51 2010
ProcCmdLine: BOOT_IMAGE=/boot/vmlinuz-2.6.35.8 root=UUID=e8a84ed2-696e-4c59-b2c6-0df091211846 ro splash
ProcEnviron:
 LANG=de_DE.utf8
 SHELL=/bin/bash
SourcePackage: dhcp3

** Affects: dhcp3 (Ubuntu)
     Importance: Undecided
         Status: New


** Tags: amd64 apport-bug maverick

-- 
dhclient assigns all interfaces connected to a bridge addresses
https://bugs.launchpad.net/bugs/677153
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