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Re: network card bridging failing on wheezy

On 09/11/14 05:27 AM, Christian Seiler wrote:

Am 08.11.2014 23:57, schrieb Gary Dale:

For some reason my network card bridging has failed after working
properly for many years.

My /etc/network/interfaces is:

auto lo
iface lo inet loopback
iface eth0 inet manual
auto br0
iface br0 inet static
          address 192.168.1.14
          netmask 255.255.255.0
          broadcast 192.168.1.255
          gateway 192.168.1.1
          bridge_ports eth0
          bridge_stp off
          bridge_fd 0
          bridge_maxwait 0

  From a fresh boot, I get nothing running.

What does

  ip link show

and

  ip -4 addr show

say?

Note that in configurations where I use bridging, I don't have a 'iface
eth0 inet manual' line; since 'bridge_ports eth0' is set, this will
automatically activate 'eth0' as part of the bridge. But OTOH, I don't
see the harm that line can do...
That gets a little tricky if I do it after a fresh boot because I have no network running. However, in my current up and running state (eth0 given the 192.168.1.14 IP) ifconfig returns 

eth0      Link encap:Ethernet  HWaddr 00:24:1d:14:d8:42
          inet addr:192.168.1.14  Bcast:192.168.1.255 Mask:255.255.255.0
          inet6 addr: 2002:c654:a32b:0:224:1dff:fe14:d842/64 Scope:Global
          inet6 addr: fe80::224:1dff:fe14:d842/64 Scope:Link
          UP BROADCAST RUNNING MULTICAST  MTU:1500  Metric:1
          RX packets:531054 errors:0 dropped:0 overruns:0 frame:0
          TX packets:535919 errors:0 dropped:0 overruns:0 carrier:0
          collisions:0 txqueuelen:1000
          RX bytes:143598255 (136.9 MiB)  TX bytes:296648201 (282.9 MiB)
          Interrupt:41 Base address:0xe000

lo        Link encap:Local Loopback
          inet addr:127.0.0.1  Mask:255.0.0.0
          inet6 addr: ::1/128 Scope:Host
          UP LOOPBACK RUNNING  MTU:16436  Metric:1
          RX packets:6945 errors:0 dropped:0 overruns:0 frame:0
          TX packets:6945 errors:0 dropped:0 overruns:0 carrier:0
          collisions:0 txqueuelen:0
          RX bytes:6807129 (6.4 MiB)  TX bytes:6807129 (6.4 MiB)

vnet0     Link encap:Ethernet  HWaddr fe:54:00:40:68:c8
          inet6 addr: fe80::fc54:ff:fe40:68c8/64 Scope:Link
          UP BROADCAST RUNNING MULTICAST  MTU:1500  Metric:1
          RX packets:4636 errors:0 dropped:0 overruns:0 frame:0
          TX packets:45 errors:0 dropped:0 overruns:0 carrier:0
          collisions:0 txqueuelen:500
          RX bytes:575878 (562.3 KiB)  TX bytes:5876 (5.7 KiB)

ip link shows
1: lo: <LOOPBACK,UP,LOWER_UP> mtu 16436 qdisc noqueue state UNKNOWN mode DEFAULT group default 
    link/loopback 00:00:00:00:00:00 brd 00:00:00:00:00:00
2: eth0: <BROADCAST,MULTICAST,UP,LOWER_UP> mtu 1500 qdisc pfifo_fast state UP mode DEFAULT group default qlen 1000 
    link/ether 00:24:1d:14:d8:42 brd ff:ff:ff:ff:ff:ff
4: br0: <BROADCAST,MULTICAST> mtu 1500 qdisc noqueue state DOWN mode DEFAULT group default 
    link/ether fe:54:00:40:68:c8 brd ff:ff:ff:ff:ff:ff
5: vnet0: <BROADCAST,MULTICAST,UP,LOWER_UP> mtu 1500 qdisc pfifo_fast master br0 state UNKNOWN mode DEFAULT group default qlen 500 
    link/ether fe:54:00:40:68:c8 brd ff:ff:ff:ff:ff:ff

ip -4 addr shows
1: lo: <LOOPBACK,UP,LOWER_UP> mtu 16436 qdisc noqueue state UNKNOWN group default 
    inet 127.0.0.1/8 scope host lo
2: eth0: <BROADCAST,MULTICAST,UP,LOWER_UP> mtu 1500 qdisc pfifo_fast state UP group default qlen 1000 
    inet 192.168.1.14/24 brd 192.168.1.255 scope global eth0
4: br0: <BROADCAST,MULTICAST> mtu 1500 qdisc noqueue state DOWN group default 
    inet 192.168.1.14/24 brd 192.168.1.255 scope global br0



If I bring up br0 (ifconfig
br0 up), it comes up with 192.168.122.1 whether I do it with eth0 up or
down.

This IP seems oddly familiar... Did you recently install libvirt?
Because that's the default IP for libvirt's default internal bridged
network (virbr0). Normally, that shouldn't interfere with the standard
bridge (different interface name), but maybe in your case, perhaps
because you edited your configuration?

(XML configuration under /etc/libvirt/qemu/networks/, especially look
for symlinks in /etc/libvirt/qemu/networks/autostart/. Note that if you
manually edit your libvirt configuration without virt-manager or virsh,
you first have to stop it, edit the configuration and then start it
again, else it will not work and be overwritten.)
I've had libvirt install for quite a while, I believe. I've been using kvm and virt-manager for years. There is a symlink (default.xml) that points to default.xml in the parent directory (using the full path name). That file does use the 192.168.122. address range. 


Bringing up br0 with the 192.168.1.14 address leaves me with a machine
that can't connect or be connected to.

Is bridge-utils still installed? What does 'brctl show' say?

- Christian


brctl show returns

bridge name     bridge id               STP enabled     interfaces
br0             8000.fe54004068c8       yes             vnet0
Subsequent to this, I changed the default.xml package to use my local subnet addresses. When I rebooted, the br0 IP was correct but nothing else was up. Even after bringing up lo and eth0 and adding a default gateway, my machine was still not reachable on the network.
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