[Bug 692775] [NEW] linking two virtual machines does not work

Mon Dec 20 22:03:03 GMT 2010

Public bug reported:

Binary package hint: bridge-utils

Configured bridge:

auto br8
iface br8 inet static
  address 172.16.28.1
  netmask 255.255.255.0
   bridge_fd 9
  bridge_hello 2
  bridge_maxage 12
  bridge_stp on
  bridge_ports eth0.6
  post-up iptables -t nat -A POSTROUTING -s 172.16.28.0/24 ! -d 172.16.28.0/24 -p tcp -j MASQUERADE --to-ports 1024-65535
  post-up iptables -t nat -A POSTROUTING -s 172.16.28.0/24 ! -d 172.16.28.0/24 -p udp -j MASQUERADE --to-ports 1024-65535
  post-up iptables -t nat -A POSTROUTING -s 172.16.28.0/24 ! -d 172.16.28.0/24 -j MASQUERADE
  post-up iptables -t filter -A FORWARD -d 172.16.28.0/24 -o br8 -m state --state RELATED,ESTABLISHED -j ACCEPT
  post-up iptables -t filter -A FORWARD -s 172.16.28.0/24 -i br8 -j ACCEPT
  post-up iptables -t filter -A FORWARD -i br8 -o br8 -j ACCEPT
  post-up iptables -t filter -A FORWARD -o br8 -j REJECT --reject-with icmp-port-unreachable
  post-up iptables -t filter -A FORWARD -i br8 -j REJECT --reject-with icmp-port-unreachable

Interface is configured as expected:
br8       Link encap:Ethernet  Hardware Adresse 00:24:1d:df:f0:38  
          inet Adresse:172.16.28.1  Bcast:172.16.28.255  Maske:255.255.255.0
          inet6-Adresse: fe80::224:1dff:fedf:f038/64 Gültigkeitsbereich:Verbindung
          inet6-Adresse: 172.16.28.1/96 Gültigkeitsbereich:Global
          UP BROADCAST RUNNING MULTICAST  MTU:1500  Metrik:1
          RX packets:1990 errors:0 dropped:0 overruns:0 frame:0
          TX packets:7 errors:0 dropped:0 overruns:0 carrier:0
          Kollisionen:0 Sendewarteschlangenlänge:0 
          RX bytes:365337 (365.3 KB)  TX bytes:706 (706.0 B)

iptables are configured as expected:

Chain INPUT (policy ACCEPT)
target     prot opt source               destination         

Chain FORWARD (policy ACCEPT)
target     prot opt source               destination         
ACCEPT     all  --  anywhere             172.16.28.0/24      state RELATED,ESTABLISHED 
ACCEPT     all  --  172.16.28.0/24       anywhere            
ACCEPT     all  --  anywhere             anywhere            
REJECT     all  --  anywhere             anywhere            reject-with icmp-port-unreachable 
REJECT     all  --  anywhere             anywhere            reject-with icmp-port-unreachable 

Chain OUTPUT (policy ACCEPT)
target     prot opt source               destination         

This bridge connects two kvm-systems:
br8             8000.00241ddff038       yes             eth0.6
                                                        vnet2
                                                        vnet9

System one:
eth4      Link encap:Ethernet  HWaddr 52:54:00:ae:6c:73  
          inet addr:172.16.28.25  Bcast:172.16.28.255  Mask:255.255.255.0
          inet6 addr: 172.16.28.25/96 Scope:Global
          inet6 addr: fe80::5054:ff:feae:6c73/64 Scope:Link
          UP BROADCAST RUNNING MULTICAST  MTU:1500  Metric:1
          RX packets:863 errors:0 dropped:0 overruns:0 frame:0
          TX packets:107 errors:0 dropped:0 overruns:0 carrier:0
          collisions:0 txqueuelen:1000 
          RX bytes:69740 (69.7 KB)  TX bytes:13207 (13.2 KB)
          Interrupt:11 Base address:0x6200

Kernel IP routing table
Destination     Gateway         Genmask         Flags Metric Ref    Use Iface
172.16.28.0     0.0.0.0         255.255.255.0   U     0      0        0 eth4

On this system a dhcp-server is active. The server listens on port 67 on
all open interfaces.

System two:
eth0      Link encap:Ethernet  HWaddr 52:54:00:ae:6c:73  
          inet6 addr: fe80::5054:ff:feae:6c73/64 Scope:Link
          UP BROADCAST RUNNING MULTICAST  MTU:1500  Metric:1
          RX packets:0 errors:0 dropped:0 overruns:0 frame:0
          TX packets:0 errors:0 dropped:0 overruns:0 carrier:0
          collisions:0 txqueuelen:1000 
          RX bytes:0 (0 KB)  TX bytes:0 (0 KB)
          Interrupt:11 Base address:0x6200

Kernel IP routing table
Destination     Gateway         Genmask         Flags Metric Ref    Use Iface

Command "dhclient eth0" just times out:
Listening on LPF/eth0/52:54:00:05:cf:85
Sending on LPF/eth0/52:54:00:05:cf:85
DHCPDISCOVER on eth0 to 255.255.255.255 port 67 interval 6
DHCPDISCOVER on eth0 to 255.255.255.255 port 67 interval 12
DHCPDISCOVER on eth0 to 255.255.255.255 port 67 interval 18
DHCPDISCOVER on eth0 to 255.255.255.255 port 67 interval 17
DHCPDISCOVER on eth0 to 255.255.255.255 port 67 interval 8
No DHCPOFFERS received.
No working leases in persistent database - sleeping

No dhcp-packets are seen by the client, nor the server. Impossible to use dhcp with kvm.

ProblemType: Bug
DistroRelease: Ubuntu 10.10
Package: bridge-utils 1.4-5ubuntu2
ProcVersionSignature: Ubuntu 2.6.35-23.41-server 2.6.35.7
Uname: Linux 2.6.35-23-server x86_64
Architecture: amd64
Date: Mon Dec 20 22:31:35 2010
InstallationMedia: Ubuntu-Server 10.10 "Maverick Meerkat" - Release amd64 (20101007)
ProcEnviron:
 LC_CTYPE=en_US.UTF-8
 PATH=(custom, no user)
 LANG=de_DE.UTF-8
 SHELL=/bin/bash
SourcePackage: bridge-utils

** Affects: bridge-utils (Ubuntu)
     Importance: Undecided
         Status: New

** Tags: amd64 apport-bug maverick

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https://bugs.launchpad.net/bugs/692775

Title:
  linking two virtual machines does not work