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Date:      Thu, 18 Aug 2005 16:27:26 -0400
From:      Jim Durham <durham@jcdurham.com>
To:        Martin Hepworth <maxsec@gmail.com>
Cc:        freebsd-questions@freebsd.org
Subject:   Re: Network Interface 'overload' in 4.11
Message-ID:  <200508181627.27113.durham@jcdurham.com>
In-Reply-To: <72cf361e05081811314a56806a@mail.gmail.com>
References:  <200508181214.30511.durham@jcdurham.com> <72cf361e05081811314a56806a@mail.gmail.com>

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On Thursday 18 August 2005 02:31 pm, you wrote:
> Sounds like viral activity to me. I has this at work recently
> where 2 mtob infected machines where able to bring the entire
> 100mbs switched network to its needs  If you run ethereal you
> may find the network is being flooded by arp lookups from the
> Windows machine in question.....

Yes. I agree. Although we've run Symantec on the silly box and 
nothing is there with the latest identity files. In fact, now 
you can hook it back up to the net and all is fine. Maybe it got 
fixed by one of the 'anti-worm worms' ?  8-) .

What I was really wondering is if there is some way of preventing 
one silly Windows box from taking the FreeBSD server into a 
state where it is pretty much useless network-wise.

Setting throttling is one thing that was suggested, but as I 
recall, when I tried that, it actually made no difference 
because it throttled the interface and it was useless anyway.

Doesn't ethereal really just run tcpdump?  Tcpdump showed very 
little. I guess because it was running on the same machine and 
the machine wasn't delivering packets to the internal 
networking..or it was infernally slow and it didn't get much to 
show.

Probably if I had a 2nd FreeBSD box monitoring the network on a 
hub insdtead of a switch, that would work, but this is an "outer 
office" with no on-site IT staff and that is sort of hard to 
accomplish.

Thanks!

-Jim



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