Thanks for the replies guys.

Toolie - thanks for the info on the VoIP daughter board. I do have a VoIP daughter board installed.

It's on a test bench so the IP addressing is pretty tightly controlled. What's weird is the problem is intermittent. When it doesn't work, I'm unable to access WebPro via either the VoIP or standard ethernet interfaces. When it does I can use either. It's a bit of a weird one so I'm also starting to think I've overlooked something simple.

I'm attempting to debug with Wireshark at the mo so I'll see how it goes and keep a special eye out of IP conflicts.