Question : IP Conflict not on arp table

We are on MS Server 2000 running as the network DNS.  We started having problems sending so we rebooted the server.  When it came back up, it stated that there was an IP conflct (running static).  When we restared our ISA server, it also came up with an IP address conflict error.  When we look on the arp table there is nothing listed for the ip address.  In both instances, the ip address appear to be correct and unique.

Answer : IP Conflict not on arp table

If an IP conflict is detected then the IP will be 0.0.0.0.

IPCONFIG /all will reveal all the IP information

Try going to another machine and ping the IP address and see if another computer responds eg
ping x.x.x.x
You could also try
ping -a x.x.x.x
and try and return the computer name

Chances are there IS another machine on your network with the same IP - you just have to find it !

If you are using DHCP check that the IP is not witin the scope of addresses being issues (or it is excluded). Also check that you don't have muliple DHCP servers with overlapping scopes.