Hi Everyone!

I have server which has "Xen/debian" installed. On this there is a virtual machine which has "Debian" installed. This virtual machine is used as a dhcp server for the network. Since yesterday, its not leasing any ip address! when i connect its ethernet cable to switch it says "eth0: received packet with its own address as IP address".

the only thing that i remember (which might have caused the problem) is adding a mirror server(a different machine). The dhcp server gave it the address 192.168.1.1(the network is 192.168.1.0/24) and it was working fine. anyone knows how to solve the problem?

Regards,

This sounds like you have two machines with the same address, 192.168.1.1. Check the interface configuration on both machines (i.e. run ifconfig) and verify.

It is possible to run mirroring, fail-over, load sharing, DHCP servers and in fact relatively easy. I am doing so right now on my own network. You need to configure them for this purpose, though, as they need to be aware of and communicate with each other. If you simply put two DHCP servers on the same network, they will conflict and both try to issue requests, read address collisions and race conditions. A simple search on the subject of backup DHCP should point you to plenty of documents on how to correctly implement this.

thanks for the reply. What i meant was that I put a machine as "Ubuntu Mirror Server". its not giving out ip addresses. It has been configured to use the ip address 192.168.1.172/24. so its just another (dhcp) client in the network.

Have you looked at the DHCP logs? At the very least there should be something in syslog that indicates DHCP traffic, for example DHCPREQUEST and DHCPACK statements. Also look to see what interface and port DHCP is listening on. Netstat should tell you this. After you confirm that these are correct, you can try to test it by watching the traffic with a sniffer. Unfortunately, since DHCP works on broadcasts, you can't telnet into it, but you should be able to see the traffic.