Re: [Xen-users] Routing problem in bridged setup

["Todd Deshane" <deshantm@xxxxxxxxx>]

On Fri, May 9, 2008 at 2:50 PM, Pepe Barbe <elventear@xxxxxxxxx> wrote:

On May 9, 2008, at 12:45 PM, Todd Deshane wrote:

I just wanted to make sure that you are aware of the Ubuntu bugs:
https://bugs.launchpad.net/ubuntu/+source/xen-3.2/+bug/204010
https://bugs.launchpad.net/ubuntu/+source/linux/+bug/218126

Yeah, I as aware of those problems and I have used the suggested solutions (Hirano's Kernel) with success. After that everything I wanted to do has been working with Xen, until now.

There are a number of troubleshooting techniques discuss in those bugs
including:

*using ethtool commands
*looking at the bridges in more detail with brctl commands etc.
*manually tracing the traffic with tools like wireshark and tcpdump
*any of general networking debugging that you can think of

I've used tcpdump to trace the traffic. What I have seen is the following.

Traffic outgoing from from domU-dmz traverses successfully to the brdmz bridge in domU-firewall and from there it goes to the eth0 interface that is part of the eth0 bridge in dom0. But no traffic shows in the eth0 bridge in dom0 or through vif1.0.

Traffic going from dom0 to domU-dmz reaches successfully but again any replies or acks don't come back. Thus I am not able to connect successfully.

I've flushed the iptables in dom0 to make sure nothing could be affecting it, but it help anything. dom0 etho or vif1.0 do work, at least partially, as I am using those interfaces for LAN forwarding to do NAT in domU-firewall. There is no problem with that.

Any ideas of what other step or where in the Linux system I could to see what is going on with the eth0 bridge or vif1.0 interface in dom0?

There is a couple of things that I would take a look at that can be found here:
http://wiki.xensource.com/xenwiki/XenNetworking
 

In particular, I know there were sometimes issues with:
/proc/sys/net/ipv4/ip_forward

You may also want to get a better understanding for ebtables and its interaction with things.
A link off of that page is:
http://ebtables.sourceforge.net/br_fw_ia/br_fw_ia.html

We also may have some links that you would find useful from our Networking chapter:
http://runningxen.com/chapters/chapter10/

Hope that gives you some places to look.

Cheers,
Todd
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