bridged networking setup

[Neal Becker]

I followed the advice here:

http://wiki.libvirt.org/page/Networking#Bridged_networking_.28aka_.22shared_...

Working, but one thing strange.

My enet I/F on the host used to be eth1.  Now it says it's the bridge br0.
Is this as expected?

br0       Link encap:Ethernet  HWaddr 00:E0:81:B1:49:F8  
          inet addr:10.32.111.113  Bcast:255.255.255.255  Mask:255.255.255.0
          inet6 addr: fe80::2e0:81ff:feb1:49f8/64 Scope:Link
          UP BROADCAST RUNNING MULTICAST  MTU:1500  Metric:1
          RX packets:1665233 errors:0 dropped:0 overruns:0 frame:0
          TX packets:2446635 errors:0 dropped:0 overruns:0 carrier:0
          collisions:0 txqueuelen:0 
          RX bytes:173668560 (165.6 MiB)  TX bytes:2928481244 (2.7 GiB)

eth1      Link encap:Ethernet  HWaddr 00:E0:81:B1:49:F8  
          inet6 addr: fe80::2e0:81ff:feb1:49f8/64 Scope:Link
          UP BROADCAST RUNNING PROMISC MULTICAST  MTU:1500  Metric:1
          RX packets:5073158 errors:0 dropped:0 overruns:0 frame:0
          TX packets:5066467 errors:0 dropped:0 overruns:0 carrier:0
          collisions:0 txqueuelen:1000 
          RX bytes:3649574236 (3.3 GiB)  TX bytes:5083712432 (4.7 GiB)
          Interrupt:17 Memory:fdee0000-fdf00000

Setup:
cat /etc/sysconfig/network-scripts/ifcfg-eth1
# Intel Corporation 82573V Gigabit Ethernet Controller (Copper)
DEVICE=eth1
HWADDR=00:e0:81:b1:49:f8
ONBOOT=yes
DHCP_HOSTNAME=nbecker6
BOOTPROTO=dhcp
TYPE=Ethernet
USERCTL=no
PEERDNS=yes
IPV6INIT=no
NM_CONTROLLED=no
BRIDGE=br0

cat /etc/sysconfig/network-scripts/ifcfg-br0
DEVICE=br0
TYPE=Bridge
BOOTPROTO=dhcp
ONBOOT=yes
DELAY=0
NM_CONTROLLED=no
DHCP_HOSTNAME=nbecker6
STP=on

[compdoc]

> My enet I/F on the host used to be eth1.
> Now it says it's the bridge br0. Is this as expected?

Well, the interfaces are doing exactly what you specified in the ifcgf
scripts. I dunno if that's what you expected or not...

When I use bridges, I don't let the interface or the bridge obtain an IP
address since they don't need them. But I can't tell what you're doing with
the bridge.

Is there no eth0?

[Neal Becker]

compdoc wrote:
> > My enet I/F on the host used to be eth1.
> > Now it says it's the bridge br0. Is this as expected?
>
> Well, the interfaces are doing exactly what you specified in the ifcgf
> scripts. I dunno if that's what you expected or not...
>
> When I use bridges, I don't let the interface or the bridge obtain an IP
> address since they don't need them. But I can't tell what you're doing with
> the bridge.
>
> Is there no eth0?

There is nothing plugged in to eth0.

My uplink is eth1.

The bridge is only for use by virtual machines on this same box.

Should I have configured it differently?

[compdoc]

> There is nothing plugged in to eth0.
>
> My uplink is eth1.
>
> The bridge is only for use by virtual machines on this same box.
>
> Should I have configured it differently?

I always use 2 or more nics for servers running virtual machines, with each
nic connected directly to the main switch.

If the host and guests are sharing the same nic, each will have less
bandwidth. The same is true of sharing anything: cpus, hard drives, network
cables, etc. More is always better.

Your scripts look fine but could be cleaned up a little. However, if it's
working leave it alone.

Also, I don't use STP myself and what little I know of it leads me to
believe it's a security risk.