Any hints on how to do this?

We have a situation where some person has broadcast a route which is mapping one of our subnets to the wrong place. I'm trying to track this at the Mae's to find out what's going on, but I'm really interested in figuring out how one can prevent this sort of thing or find out the original source of the bad route.

Resolving the issue should be straight forward: - traceroute to something on that subnet from a few places (see http://www.boardwatch.com/isp/trace.htm amongst others) - get a phone number for the noc or whatever of the org that announcing your routes, (try whois, or possibly their web page... (whatever, get creative)) - give them a call and explain the situation, open a ticket if they have a ticketing system, and move forward from there You may have to convince them that the problem exists, by forwarding on traceroute info or whatever. Hopefully their noc staff will be helpful, reasonable, and clueful. I have no suggestions for how to prevent this problem from occurring. Hope this helps, davec