[TriLUG] Networking and Fedora

[Joseph Tate]

Well, that went poorly.

As soon as I issued the brctl command my whole network went dark.  The
shell I was working in hung, and I forcefully disconnected to the top
level ssh shell instead of the sub shell.  Now I can't connect to that
host machine, or even the other machine that I was using to connect
through it.  I guess it'll have to wait until I get home to fix it up.
 That'll teach me to troubleshoot network issues remotely... :/

On Wed, May 26, 2010 at 2:50 PM, Justis Peters <jtrilug at indythinker.com> wrote:
> Jeff Schornick wrote:
>> Preparing to make a fool of myself...
>>
>>> 10.2.2.0        0.0.0.0         255.255.255.0   U     0      0        0 eth0
>>> 10.2.2.0        0.0.0.0         255.255.255.0   U     0      0        0 br0
>>>
>> You appear to have two routes to the same destination subnet, equal
>> metric to two different interfaces.  Since eth0 and br0 aren't
>> currently bridged, I'd imagine this would lead to rather inconstant
>> delivery.  I'm honestly not sure how the kernel choses which route to
>> use under these circumstances, but I'm 99% sure it won't deliver each
>> packet to both.
>>
>> Do you perhaps want eth0 part of the br0 bridge group?
>>
> Didn't see your reply before I sent mine. I think you've got it nailed,
> Jeff. I hadn't noticed that eth0 is not yet attached to br0.
>
> The way that Xen users frequently do this is to rename the "real" eth0
> to peth0 and then name the bridge itself eth0. You would then add peth0
> to the bridge, along with all the virtual interfaces for the guest VMs.
> Some people find this confusing; others like it.
>
> Joseph: The quick way to test our theory would be to remove the second
> route and then add eth0 to the br0 bridge. The commands should look
> something like this:
>  route del -net 10.2.2.0/24 br0
>  brctl addif br0 eth0
>
> I'm not sure of the preferred way to make those changes persistent in
> Fedora, but I'm sure the answer is online and easy to find. Also note
> that you probably want to run them in the order listed above. I suspect
> that reversing the order might create a feedback loop between the
> routing table and the bridge.
>
> Best of luck and let us know how it goes.
>
> Kind regards,
> Justis
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-- 
Joseph Tate
Personal e-mail: jtate AT dragonstrider DOT com
Web: http://www.dragonstrider.com