Hi - I have a machine which was originally built with Centos 5.0 including xen. It has all the current updates and here are some questions: The current problem is: 1) If I boot the non-xen kernel - it runs fine. If I boot the xen kernel - it boots - but has no network connectivity - and I get the following errors continuously in the messages log: Time/date: C5 Kernel: vif0.0: received packet with own address as source address. And another question: 2) The Centos 5.1 release notes say that the 5.1 xen release includes dnsmasq, and that this may conflict with dhcpd and named if you are running these. I am running both - and i thought dnsmasq was not running because it is set to "not start at boot" - but I now notice that it is "running" even though it is set to "not start on boot". This is true whether I boot the xen or non-xen kernel. Is this a problem - and if so - how do I stop it from running? How do dnsmasq and dhcpd both function without breaking each other? Now some detailed background: The machine uses a Realtek 8111B network adaptor - and this has been a problem all along. I used to manually reinstall the r1000 driver (apparently the correct driver for the adaptor) every time the kernel was updated. Tedious - but it worked. My xen kernel worked fine. Some months back - a bunch of updates came through corresponding to the release of Centos 5.1 - and my normal driver re-install didn't seem to get the Xen kernel running. On advice from the Centos forums - I installed the dkms-r1000 driver - and eventually got the non-xen kernel running fine - but couldn't get the xen kernel running. Every boot - the message "starting eth0 - Failed" would come up. I have been using the non-xen kernel ever since. My system has both kernel-devel and kernel-xen- devel installed. Just yesterday - I installed the latest Kernels ( kernel 2.6.18-53.1.6.el5 <https://192.168.0.201:10000/software/edit_pack.cgi?search=kernel&package=kernel&version=2%2E6%2E18%2D53%2E1%2E6%2Eel5>) - using gnome software updater which installs both xen and non-xen kernels. The non-xen kernel worked fine without any manual driver install. Presumably the dkms install worked fine. When I tried to boot the xen kernel - there were lots of problems - partly because I recently got the shcpd going on the server - and it now needs static ips. The xen kernel still seemed to be set to dynamic ips - but that was easily fixed. Now the message "starting etho - OK" is displayed - and nearly everything looks OK in the startup messages - but several things are slow to start. Once it boots - there is no network connectivity - and the above "vif0.0" errors appear in the messages log. Can anyone shed any light on these questions? Thanks Richard.