On Jan 8, 2008 2:04 PM, Chris Gow <chris.gow at gmail.com> wrote: > Hello: > > I'm having issues with my CentOS 5.1/Xen installation. If I run the > xen-bridge, I seem to get flaky ethernet. By flaky I mean everything seems > fine from the host machine, but if I attempt to contact the host machine > from > another remote machine (eg. my laptop which is on the same subnet as the > xen > machine, separated by 10 ft of cable and a router) I either get extremely > high ping times or Destination Host Unreachable. Ditto with ssh. I've > disabled the firewall and it does not make a difference. If I stop the > xen-bridge (/etc/xen/scripts/network-bridge stop) then I get what I would > consider normal network access to the xen machine. > > Hardware: Gigabyte GA-G33M-S2H MB (Realtek R8110SC onboard nic) > OS: CentOS 5.1 64bit Xen > > I installed CentOS last night with the Xen kernel, the stock kernel did > not > support my nic which I was aware of. So I downloaded the r1000 source rpm > from the centos wiki, built and installed it. Once I did that the card was > detected (an ifconfig would actually display eth0), but it would never get > an > IP address (the xen machine is configured for dhcp at the moment). Today, > I > installed the non-xen kernel, applied the non-xen r1000 kernel module and > the > onboard nic was found and working. > > I then grabbed the updates from centos, saw that there were some kernel > updates, applied the r1000 kernel modules again, restarted and (the > non-xen > kernel) eth0 was still happy. Good. Restarted again, but booted into the > xen > kernel, eth0 was still happy. eth0 would get an IP address, and was able > to > see the outside world. However, the outside world (eg. my laptop) could > not > see the xen machine or it could inconsistently. That is, ping times would > be > extremely high (on the order of 2+ seconds) or I would get Destination > Host > Unreachable errors. Trying to connect via ssh would also be sporadic. > > Thinking it might be firewall related, I disabled the firewall. There was > no > change in behaviour. I then disabled the xen-bridge and was able to ping > with > reasonable numbers (<200ms) and connect via ssh. Just to note though, > after I > stopped the bridge I immediately tried to connect via ssh/ping and did not > get through, so I ran service iptables stop (again) and then was able to > get > correct network access. I'm not sure if stopping iptables again did > anything > (I doubt) or I did not leave enough time from stopping the bridge to > letting > everything get reconfigured. > > I'm not sure what the problem is or how exactly to troubleshoot it. The > NIC is > slightly different than the one specified in the CentOS wiki (the wiki > mentions RTL8110 and RTL8169SC and mine is a RTL8110SC) but I'm not > familiar > enough with the devices to know how much of a big deal that is, if any. > Also, > just to be clear, the problem is other physical machines have a difficult > time accessing the xen host pc when the xen-bridge is running. I have not > gotten as far as creating a VM yet. > > Any assistance would be great. > > thanks > > -- chris > _______________________________________________ > CentOS mailing list > CentOS at centos.org > http://lists.centos.org/mailman/listinfo/centos > Chris, I got the impression that the network setup is as this example: Your laptop (192.168.1.x/255.255.255.0) Router (192.168.1.1/255.255.255.0) Xen (192.168.1.x/255.255.255.0) Well, you can't route from one physical network to another over a router where source and destination has a ip in the same netmask area. Perhaps you only use the router as a network switch since cheaper models have a built in switch... In this case it's a switch rather then a router, some lousy home scale routers may rally screw up things since they don't have switches, rather a couple of network interfaces separated with bridging and firewall rules in a embedded Linux or BSD environment.. - Nicolas -------------- next part -------------- An HTML attachment was scrubbed... URL: <http://lists.centos.org/pipermail/centos/attachments/20080108/7c688fe6/attachment-0005.html>