Soren, You are correct, I cannot ping the gateway from the guest - however I can from the host. The output of 'brctl show' on the host is as follows ## START brctl output ### $brctl show bridge name bridge id STP enabled interfaces br0 8000.001999705a61 no eth0 vnet0 ## END brctl output ## From looking at this it looks like I should have my guest configured to use the vnet0 interface instead of br0? Why when the testbox.xml VM configuration file is configured to use br0 is vnet0 being created when I start the VM via virsh? brtables has not been modified in any way. Serge, thanks for your input but I can't really do a traceroute easily because I can't connect this guest to the internet to download any packages or dependancies for the tcptraceroute program. It's really strange, the host and the guest communicate fine. Any more ideas? Kind Regards, Jamie. <div class="gmail_quote">On Wed, Jun 9, 2010 at 12:26 PM, Soren Hansen <<a href="mailto:soren@ubuntu.com">soren@ubuntu.com</a>> wrote: <blockquote class="gmail_quote" style="margin: 0pt 0pt 0pt 0.8ex; border-left: 1px solid rgb(204, 204, 204); padding-left: 1ex;"><div class="im">On Wed, Jun 09, 2010 at 08:49:10AM +0100, Jamie McDonald wrote: > These changes have been enabled and I can still ssh between both the > host and the guest, but still no external conectivity for the guest. </div>Just to be clear, you can't even ping e.g. 88.208.248.1, right? Can you provide the output of "brctl show" on the host, please? I assume you haven't played with brtables or anything like that? -- <div><div></div><div class="h5">Soren Hansen Ubuntu Developer <a href="http://www.ubuntu.com/" target="_blank">http://www.ubuntu.com/</a> </div></div> -----BEGIN PGP SIGNATURE----- Version: GnuPG v1.4.10 (GNU/Linux) iEYEARECAAYFAkwPen4ACgkQonjfXui9pOMnsACeMqfOJ/09n/UmegCtvvkYhAQf Fe0AniysDF8qAxKhwS8e6CqPt/GgwxgI =Tw8I -----END PGP SIGNATURE----- </blockquote></div>