On Fri, Apr 24, 1998 at 06:06:50PM -0500, John A. Tamplin wrote:
On Fri, 24 Apr 1998, Karl Denninger wrote:
Well, there is a simple knob for this: If the Knob is turned "ON", then any packet from a source address which is not routed to the interface it came in on is dropped. This works for static, dynamic, and all other kinds of routing. It will solve the problem and is trivial to implement - if any of the vendors care.
It doesn't work for asymmetric routing as you describe it above. If you modify your criteria to be that there are no valid routes out that interface, you would only break transient routing conditions, but depending on how the router stores routes it may not be possible (or desirable due to memory requirements) to implement.
Yeah, John, we know that. But I've rarely seen a /32 with asymmetric routing. The vast majority (I speculate) of these problems happen on the far side of border routers which are unlikely to be participating in ASR, are they not? How far down is it being used? Cheers, -- jra -- Jay R. Ashworth jra@baylink.com Member of the Technical Staff Unsolicited Commercial Emailers Sued The Suncoast Freenet "Two words: Darth Doogie." -- Jason Colby, Tampa Bay, Florida on alt.fan.heinlein +1 813 790 7592 Managing Editor, Top Of The Key sports e-zine ------------ http://www.totk.com