Many thanks to all those who replied. It did turn out to be a filter that needed updating at 7018, which was very quickly fixed by their team. -----Original Message----- From: Brian Wallingford [mailto:brian@meganet.net] Sent: Wednesday, 5 November 2008 2:06 PM To: Charles Gucker Cc: Campbell, Alex; nanog@nanog.org Subject: Re: AT&T routing issue :In short yes. AT&T uses a customer specific access list to perform a :uRPF like function. That is, if your provider did not request for :their provider to have AT&T update their filter. Indeed. We've used ATT MIS for many years and have been happy with their policies (which have blunted quite a few DDOS attacks), and their response to acl mod requests. They do tend to take longer than I'd like (on the order of several business days) for standard requests, though if you request expedition, response time is impressive. Overall, thumbs up. :AT&T MIS Maintenance :888-613-6330 Prompt-3, 2 :rm-awmis@ems.att.com Yep. Always quite responsive. As with any other vendor, if you feel the person handling the call isn't qualified, escalate.