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

From: Martin Foote <martin_foote [izzat] hotmail.com>
Date: Wed Feb 08 2006 - 16:45:56 EST


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 time.

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
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Received on Wed Feb 8 19:02:01 2006

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