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RE: AT&T Blocking ICMP (was RE: AT&T US Network Slowdown?)
From: "Ingevaldson, Dan (ISS Atlanta)" <dsi () iss net>
Date: Tue, 19 Aug 2003 12:29:54 -0400

The "Nachi" worm propagates via MSRPC DCOM and the IIS WebDAV bug.  It
may be causing this storm because it runs 300 scanning threads, and it
pings each IP first.


MS Blast wasn't multithreaded.

Daniel Ingevaldson
Engineering Manager, X-Force R&D
dsi () iss net 
Internet Security Systems, Inc.
The Power to Protect

-----Original Message-----
From: Paul Jasa [mailto:pjasa () univision net] 
Sent: Tuesday, August 19, 2003 12:19 PM
To: nanog () merit edu
Subject: AT&T Blocking ICMP (was RE: AT&T US Network Slowdown?)

A call to AT&T Worldnet confirms that AT&T Worldnet service is blocking
ICMP in order to deal with an undefined emergency.  Nothing posted on
their site, nor any other info is available.  If anyone has info related
to this "icmp outage", please advise.  Thanks! pj

Paul Jasa 
Network Engineer 

-----Original Message-----
From: Sean Crandall [mailto:sean () megapath net]
Sent: Tuesday, August 19, 2003 02:12 AM
To: Paul Jasa; nanog () merit edu
Subject: RE: AT&T US Network Slowdown?
Importance: High

Dear Nanogers,
Is anyone aware of a "slowdown" issue throughout the US AT&T
network since 8/18 at around 4pm which is causing a lot of 
internet circuits (including DSL) to be inaccessible and/or 
appear down from the outside world?  AT&T says this has been 
escalated to "Level 4" with no ETA and affecting the whole 
country.  I am seeing this problem in the San Francisco area. 
 Just wondering if anyone else is experiencing anything that 
would confirm AT&T's claim, and fishing for more info about 
the possible cause and ETA.  Thanks!

We are currently seeing the slowdown on our network in San Jose.
Started about exactly the time frame that you mentioned.  The rest of
the country
(oddly) seems unaffected by this at the moment, but San Jose is getting
hammered by something.

Still trying to sort out exactly where it is coming from.


Sean P. Crandall
VP Engineering Operations
MegaPath Networks Inc.
Pleasanton, CA  94588
(925) 201-2530

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