nanog mailing list archives

Re: Level(3) filtering (was Yahoo outage summary)


From: Roland Dobbins <rdobbins () cisco com>
Date: Mon, 9 Jul 2007 20:26:54 -0700



On Jul 9, 2007, at 8:10 PM, Chris L. Morrow wrote:

In the
number of customer conversations I've had about this it's always sort of surprising that people think it's 'ok' to not have a prefix-list : ( cause, guess what: "if you don't have one and they don't have one... THEY will
get you eventually"

Many folks seem to think that they'll be OK because 'someone else' will be doing this for them, and so they're protected. They also don't think about the fact that they themselves could accidentally cause a problem for others (and, in some cases, for themselves, by acting as an inadvertent sinkhole). But when it's explained to them that a) if everyone thinks that 'someone else' will do the appropriate filtering, then nobody will do it, and b) that they can end up hosing themselves and also taking a big reputational hit, most people I talk to about this seem to understand.

The problem is that this is largely an ad-hoc, 1:1 type of educational effort, which doesn't scale well. And in many cases, folks seem to find it difficult to go to their management and explain that they must invest the opex to implement and maintain these policies (along with BCP38, iACLs, et. al.); sort of an inversion of "The Emperor's New Clothes", heh.

-----------------------------------------------------------------------
Roland Dobbins <rdobbins () cisco com> // 408.527.6376 voice

       Culture eats strategy for breakfast.

               -- Ford Motor Company




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