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RE: Worm / UDP1434

  • From: Freedman David
  • Date: Sun Jan 26 05:34:33 2003

 This is exactly what we had to do, we couldn't even get to the boxes,
I had a NOC engineer go and console them out of band and run a 
"sh port util" to find out whom the offenders were, before disabling their

Extreme were unhelpful, suggesting that we apply the ACL (advisory released
~6 hours after we had done it!) which really made no difference.

As for multicast, I'd made sure that all VLANs had IGMP,IGMP SNOOPING and
IPMC FORAWRDING disabled, but it made no real difference....


-----Original Message-----
From: sjk
Cc: neil@DOMINO.ORG;;
Sent: 1/26/03 5:18 AM
Subject: Re: Worm / UDP1434

This is true -- the acls don't reduce the tBGTask or the tNetTask -- nor
does disabling ip forwarding on the vlan. We have around ten of these,
and they were hit particularly hard today. You actually have to shut
down the offening hosts to set the switches right.

On 25 Jan, Andy Walden wrote:
> On Sat, 25 Jan 2003, Neil J. McRae wrote:
>> >
>> > Anybody here on list using Extreme products
>> > (Summit/Alpine/Blackdiamond)? They sure don't like this traffic one
>> > bit. It causes them to not only drop traffic, but spew out every
>> > available error message under the sun...
>> >
>> > Extreme are apparently assembling an "advisory TAC" on this, from
>> > our point of view, since we use the devices to do l3 aggregation
>> > (for colo and such) we've used an ACL to try and combat the
>> > offending traffic, but its not doing much good.....
>> Do you have MCAST enabled on these switches? I'd guess this
>> is what is causing issues on the extreme boxes.
> I think the architecture is flow-based, ie, the first packet of each
> flow hits the CPU. This is probably causing the high CPU utilization.
> The flow would still hit the CPU even with a ACL and then probably be
> written to the ASIC with a null location.
> andy
> --
> PGP Key Available at

Do not taunt Happy Fun Ball.

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