RE: [load balancing] Alteon load balanced server calls to the VIP fail

From: Martin Foote <martin_foote [izzat]>
Date: Fri Feb 17 2006 - 12:39:16 EST


I have now resolved the issue also, it would appear the teaming of the
server NICs was not compatible with the load balancer and because of this it
was getting confused and trying to send the packet to the secondary NIC's
MAC, so the TCP handshake was not being completed.

So watch out for TLB configured HP teaming on Windows 2000 servers, the
configuration has now been changed to an Active-Standby setup and seems
stable 100% of the time.


Martin Foote
>From: "Martin Foote" <>
>Subject: [load balancing] Alteon load balanced server calls to the VIP fail
>Date: Wed, 08 Feb 2006 21:45:56 +0000
>I have an Alteon 2208 which I have recently upgraded to when 
>attempting to resolve another issue. I believe this is the newest version 
>of software and has not resolved my issue.
>Problem is that I have 2 load balanced servers, let's call them server1 and 
>server2, these servers are required by the application to make calls to the 
>VIP which they are load balanced behind. The network setup is using Proxy 
>IP as both the Alteon and the servers being balanced are on the same LAN. 
>When the servers make calls to the VIP it fails approximately 25-50% of the 
>As far as I'm concerned the traffic flow for server1 should be:
>1. server1 makes a request to the VIP
>2. The request is source NAT'ed behind the PIP and forwarded to either 
>server1 or server2
>3. Server1 or 2 receive the request, source IP is the PIP and so response 
>should go back through the Alteon
>4. Alteon recieves return packet and uses NAT to restore destination 
>address to server1
>5. Packet is forwarded to server1
>As I said this fails approximately 25-50% of the time. It seems to work for 
>periods and then fail for periods. Has anyone else experinced this problem? 
>Have a resolution or any advice on how to progress?
>Perhaps it is getting recognized as some kind of Land Attack? What do I 
>need to get the Alteon to recognize or report this? I have check the dos 
>stats and it does not appear here, do I need to enable it elsewhere?
>Any help would be appreciated
>Thanks in advance
>Martin Foote
>The Load Balancing Mailing List
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Received on Fri Feb 17 14:45:08 2006

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