Funny thing is, I've got 2 computers on this router and they're both showing 515 open.
Originally posted by: n0cmonkey
If there is a network printer port on the router it wouldn't surprise me. You can try forwarding the port on the router to a non-existant IP. For example, if your IP range goes from 192.168.1.50 to 192.168.1.100, forward port 515 to 192.168.1.200.