come to think of it, it certainly makes it easier in the access...everything points to that... would help if there ws a "mandatory doc"..then even those "assymetric routing" chaps would anyways put it in their access :o) -rgds alok ----- Original Message ----- From: alok <alok.dube@apara.com> To: Martin <marty@supine.com>; <nanog@merit.edu> Sent: Wednesday, November 06, 2002 1:15 PM Subject: Re: Where is the edge of the Internet? heard of default routes..?.... u dont always need an iBGP full mesh u cud redistribute a bit and "default route" a bit.... okie i know now...u give me a practice doc and say "bad boy" :o)... u can redistribute im sure there is nothing bad with that.......and also u will tend to summarize a lot with default routes too.... that was my point..... the other angle being "DDoS with spoofed ips".. right? those IPs care intertnet registerd ips? now no reason that if the router B runs OSPF that u may not have an entry for the source IP... it will be there either via redistribution or via iBGP if thats the way u want it.....or covered under default.... :o) what i mean by valid is this: "registered internet IP address" in this case you may have routes to the source network anyways iva iBGP or redistribution... inspite of a "DDoS" or "assymetric cases" ....or it may be a part of the "default route"..... also agreed this default route is more on the access end most guys tend to have links between BGP routers or run iBGP etc......then the same logic applies there too.... -rgds Alok ----- Original Message ----- From: Martin <marty@supine.com> To: alok <alok.dube@apara.com> Sent: Wednesday, November 06, 2002 12:36 PM Subject: Re: Where is the edge of the Internet? $author = "alok" ;

here is the scenario

u have a bgp A ---ospf-B - bgpC router setup

what will u do on ospf -B ?

coz transit traffic can flow thru it...

how does router B know where to send packets transitting the network? you'd need to run iBGP on it or be redistributing routes from BGP into OSPF, otherwise router B is not going to pass packets appropriately.

but what i was trying to say to Valdis....was that u cant just "blindly" drop packets in the core whose source doesnt have a route...for eg ospfB is a problem in the above

that's why you don't do it blindly. :) you pick a router that has it's eyes wide open (ie. has a full table) to do RPF filtering on. marty -- Can't buy what I want because it's free. Can't be what they want because I'm me. "Corduroy" - Pearl Jam