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Date:      Tue, 17 Jul 2001 12:29:23 -0600 (MDT)
From:      "Forrest W. Christian" <forrestc@imach.com>
To:        Dev <dev@wserv8.inetu.net>
Cc:        freebsd-isp@FreeBSD.ORG
Subject:   Re: HELP NEEDED. :) ARP problems - ARP incomplete showing up on our network
Message-ID:  <Pine.BSF.4.21.0107171226200.25209-100000@workhorse.iMach.com>
In-Reply-To: <3B5438A1.B7A54A1D@wserv8.inetu.net>

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You are probably being attacked.

Make sure you have ICMP_BANDLIM in the kernel.

Look for "Limiting .... response" messages in the syslog.

increase your NMBCLUSTERS.  The max recommended is 32768.  I usually use
32767.

When this is happening see what netstat -m shows., or look at an output of
a machine which has shown this symptom and look at the max values.


On Tue, 17 Jul 2001, Dev wrote:

> Date: Tue, 17 Jul 2001 09:07:45 -0400
> From: Dev <dev@wserv8.inetu.net>
> To: freebsd-isp@FreeBSD.ORG
> Subject: HELP NEEDED. :) ARP problems - ARP incomplete showing up on our
>     network
> 
> 
> We have been having a problem for the last 24-36 hours on our network.
> 
> We have about 350 servers (50% FreeBSD, 50% NT/2000 and a few Linux)
> 
> Servers have started to be inaccessible through our router (and
> sometimes
> through other servers).
> 
> The ARP table in our router will show an INCOMPLETE next to the Arp
> entry
> which is having trouble.
> 
> These problems surface about every 30 minutes and servers will go down
> about every 4 hours.
> 
> This problem seems to affect ONLY FreeBSD servers (and 2 Cobalt/Linux
> servers). In total, about 20-30 servers.
> 
> Does anyone have any ideas on what we can check? While our network is
> largely flat, we do route blocks of addresses directly to servers, our
> arp
> table in our router is fairly small (about 500 entries).
> 
> Any help would be greatly appreciated. We have tried a lot, but cannot
> figure out what is causing the problem. We did not have this problem
> before, and many of the servers affected have been running for 1-2 years
> 
> without any problems.
> 
> We use 3COM and Intel NIC's, Nortel switches (303, 310) and a 7206VXR
> routers.
> 
> Thanks.
> -Dev
> 
> 
> 
> To Unsubscribe: send mail to majordomo@FreeBSD.org
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> 

- Forrest W. Christian (forrestc@imach.com) AC7DE
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