[39676] in North American Network Operators' Group
Re: Code Red
daemon@ATHENA.MIT.EDU (Bill Woodcock)
Thu Jul 19 23:30:01 2001
Date: Thu, 19 Jul 2001 20:29:30 -0700 (PDT)
From: Bill Woodcock <woody@zocalo.net>
To: <nanog@merit.edu>
In-Reply-To: <20010720031208.23684.qmail@prophecy.lightbearer.com>
Message-ID: <Pine.NEB.4.33.0107192024250.12816-100000@woody.zocalo.net>
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Errors-To: owner-nanog-outgoing@merit.edu
> Reports from our monitoring systems saw the CPU usage jump by somewhere
> between 150-200% for our core routers today
I just got off the phone with the TAC about this, and received the
following _preliminary_ advice:
1) If it's not enabled, turn on CEF, to move some of the packet-forwarding
load off the processor and into hardware. For some reason, a lot of
this traffic is being process-switched, as evidenced by high "IP
Input" cpu loads.
2) If you can, put in an ACL which prohibits port-80 traffic destined _to
the interfaces of the router itself_. Since the destination IP
addresses of the packets which constitute the attack itself are
random, many of them will be addressed to your routers, rather than to
hosts, and those will _always_ be process switched, if they're not
blocked by an inbound ACL.
It goes without saying that you should have a "no http server" line in any
production router.
-Bill
