nanog mailing list archives

Re: Re[2]: SYN floods (was: does history repeat itself?)


From: Alexis Rosen <alexis () panix com>
Date: Tue, 10 Sep 1996 14:21:20 -0400 (EDT)

Alec H. Peterson writes:

Alexis Rosen writes:
That's why I was talking about filtering at a router just upstream from
the dial-access box.

FWIW, even with a thousand very busy modems, I'm pretty sure that even a
small cisco is up to the job. They just don't generate all that much traffic.

Could be, although I'd want to see this before I bet the farm on it.
I'm not sure how efficient crisco's filtering algorithm is...

I would. As a point of reference, we have filters on two fairly busy T1s,
which between them account for more then 500 modems worth of traffic and
a *lot* more besides (all of VTW's traffic, for example). Putting filters
on these, both an an AGS+/4, didn't make an enormous difference in CPU- it's
still <30%. Surely a 2500 series box could handle that much. (It's 68030 vs.
68040, but we're at 30% utilization, and we're doing other things on that
box.)

/a
---
Alexis Rosen   Owner/Sysadmin,
PANIX Public Access Unix & Internet, NYC.
alexis () panix com
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