My apologies, allow me to make a clarification. When I mentioned NAPs, I was referring more to provider peering policies _AT_ a NAP, rather than a NAP's peering policies which of course as you pointed out would be moot. Being relegated to closed enterprise environments for the past few years, I'm trying to play catch-up and validate my previous assumption that most providers filter at a /19 boundary, etc. Regards, Jade -----Original Message----- From: Bill Woodcock [mailto:woody@pch.net] Sent: Monday, September 13, 2004 12:42 PM To: Deane, Jade Cc: nanog@merit.edu Subject: Re: Provider/NAP filtering policies On Mon, 13 Sep 2004 JDeane@sungardfutures.com wrote: > I was hoping someone could point me in the direction of provider/NAP > prefix filtering policies. Most important to me is UU and Cogent, but a > concise listing of notables would be much appreciated. Just to clarify, NAPs or Internet exchanges are typically (like more than 99% of the time) layer-2 services, which don't pay attention to or care about layer-3 things like IP prefixes. A few have policies regarding what participants should filter on their own behalf, but of the four hundered odd exchanges currently operating out there, I don't know of any which filter prefixes themselves. Virtually all _providers_ over a certain size filter heavily, of course, and that's probably the portion of your question you'll get more (and more useful) answers to. -Bill