Button Click Events not working in NLB environment

[Adrian]

Hi,

I am running an ASP.Net application (v1.1.4322) on an NLB cluster of 2
web servers.
I have an intermittent problem where sometimes button click events do
not get registered upon postback. i.e. User clicks a button -> form
posts back -> nothing happens.

This is what I have found out so far:

1) When this problem happens, there is nothing submitted with the form.
I found this out by instaling a packet sniffer and looking at the HTTP
traffic. This is why .Net doesn't know what to do because it has no
idea which button was clicked.

2) If this happens, then no button clicks will work for the remained of
that user's session. i.e. they have to restart the browser to fix it.

3) This only happens in IE. Not Firefox.

4) I have tried running aspnet_regiis -c on the server, but that had
no effect.

5) This only happens when the servers are accessed via the NLB virtual
IP. If I access the servers directly, it never happens.

Any help would be appreciated.

Thanks,

Adrian

 

[hiriumi]

I'm assuming that you mean server side click events when you say "click
events". If that's the case, I hope you are managing state on one
server either using ASP .NET State Services or SQL Server. If not,
depending on the Affinity setting on the NLB.

But then viewstate is on the client side... maybe you stick viewstate
in session?

 

[Adrian]

Hi Hiriumi,

I am referring to serverside click events.
I'm managing state in SQL Server.
I'm using a common encryption / validation key in web.config across
both servers to validate my viewstate.

I've managed to solve my problem, although I am not entirely sure why
it was occurring:


The problem turned out to be caused by an SQL Reporting Services
website that was running on the same physical server.
Our application was hitting the reporting services site using the
Reporting Services clientside control, which does a HTTP GET request to
the reporting services website and shows the report within a frame.

I noticed that the issues seemed to occur after I ran some reports. At
first I thought this was a coincidence, but I decided to play around
with it anyway.
When I changed the permissions on the Reporting Services website to
enable anonymous access, the problem with the button clicks not working
on the application web site magically went away.

This is what I think was happening:
1) The reporting services site was running under a different IIS user
than the application web site
2) When I explicitly authenticated against the reporting services site,
it must have changed my context for both the reporting services website
AND my application's website. This looks like a MS bug, as there is no
logical explanation as to why this should happen and why this should
happen only when running through a load balancer.
3) At this point I'm guessing that IIS was getting some sort of
permissions error and sending me the wrong javascript files for my
application's website.

Hope this helps the next person with this issue.

Cheers,

Adrian