Find IP Address of Agent Pending Management

This one is driving me crazy.

I have one agent that keeps comming to "Pending Management".

I reject it, but it comes again.

I can't find the IP address of this agent, just a name which does not resolve to IP address in DNS.

I looked in the event log, but I can only find the name of that agent.

So , how can I find IP address of this agent. I've got > 300 subnets.

Thanks and regards,

Les