nanog mailing list archives

Re: Network Probes


From: "Scott McGrath" <s_mcgrath () bexair com>
Date: Fri, 10 Mar 2000 11:18:19 -0500


Thank you sir may I have another.... :-)

I had a vague recollection of that command from a 7000 session at Networkers
but I was not really sure what was required as we have mostly 2/3/4XXX series
routers around here with 7XXX and AGS+!!! (still going...) at the core

Thanks - Scott

Paul Ferguson wrote:

At 05:53 PM 03/09/2000 -0500, Scott McGrath wrote:

I cannot find anything in the literature about this attack method, As a
WILD guess
it is a mutation of one of the DDOS tools with new ports. but this
underscores the importance of martian filters on border routers and also
filtering outbounds
so that spoofed addresses cannot leave your border routers.  Cisco also has
an
obscure command to verify the path but it drops the router into process
switch mode
as I recall,  If I am wrong please correct

You're wrong.  :-)

I think you're talking about "ip verify unicast reverse-path",
or what we also call Unicast RPF, which requires CEF switching
(which is definately _not_ process level switching).

- paul




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