Hi,
My company has recently experienced an issue when posting back aspx
pages across multiple servers that were being load balanced. In a
nutshell, the problem involved initially loading the page on server A,
then posting it back to server B (because of the load balancer).
Occasionally, server B would fail to recognize the postback event and
load the page as if we're dealing with a GET request, thus losing all
the form data. Our machines were running Win2K server with .NET 1.1.
Naturally, the first thing we checked was the Machine.config file, in
order to verify all the servers had the same validationKey machine key
(a lesson we've learned from a previous occurence of the problem). But
even then, we still had the problem occurring intermittently. After
some more digging and prodding, we found out that a couple of nights
earlier, an overzealous system administrator updated some security
patches on the machines. During the update process, he also updated the
..NET version to a more recent version (1.1 SP1) on *some* of the
servers, but not all. So when the load balancer caused a page to
postback to a machine with a different version on it, it would bomb.
The reason I'm posting this information here is that while trying to
research this problem I only found suggestions to check the
Machine.config file, or to change the affinity to disable the load
balancing. As we found out from our experience, sometimes bugs are just
a matter of installing patches without warning. I'm hoping the
information I've posted here will help someone else in the future.
By the way, if you need to verify the version(s) of .NET that you have
installed on your server, I highly recommend using this free utility:
http://www.tmgdevelopment.co.uk/versioncheck.htm
Or.
