Hi Michael,

I think Andy mentioned using tcpdump in an earlier post to the mailing list:
I still have the command in a text file: tcpdump -vpni eth0 'host 212.13.19x.y'

That should show you what is still using the old IP. If you're confident that there isn't anything there of importance you can try removing the IP now and see if anything fails, that way you can easily re-add it until you fix the problem.

Daniel