nanog mailing list archives

Re: What is the most standard subnet length on internet


From: Jon Lewis <jlewis () lewis org>
Date: Mon, 22 Dec 2008 20:11:45 -0500 (EST)

On Mon, 22 Dec 2008, Seth Mattinen wrote:

Anyone running a platform that can't take a full table would apply such a filter to weed out anyone who likes to announce all of their space as /24's for "traffic engineering". If one does that and doesn't announce the aggregate as well, one could find themselves facing random black holes.

There's no "if" about it. Months ago when I and others were looking into this, we found plenty of examples of networks with /19s, /20s, etc. announcing only the /24 deaggregates. If you plan to filter these people and have customers to answer to, you'll need to point default at someone who's not filtering them.

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