Problem: GET/POST/ViewState and swapping CLIENT IP address in one session

[Tony]

I would really appreciate it if anyone has any thoughts on this one -
it's driving us mad.

We have a web site which is using ASP.NET 1.1 and which is load
balanced across two web servers with IP affinity. It generally works
very well. We have set enableViewStateMac="false" and to be sure we
have set the same machine key on each of the web servers (i.e.
<system.web><machinekey....>)

We have a particular scenario which is causing us big headaches.

Certain clients are connecting to our services via proxy servers or
gateways which result in the client appearing to have different IP
addresses during the same session. i.e. load the page, press F5 a few
times, and different client IP addresses are presented. AOL proxy
servers exhibit this behaviour.

The client can successfully navigate around the site - even if they are
switched between servers. HOWEVER if they GET a page from one of the
web servers and end up POSTing to the other, ASP.NET is interpreting
the POST as a GET. We have enabled detailed logging and we can see the
HTTP header, which is a POST. We also have logging in the page itself
and we can clearly see that Page.IsPostBack is set to false. Why is
ASP.NET seeing our POST as a GET?

Does anyone have any idea what is happening and how we can resolve this
issue?

I am guessing that viewstate is somehow coming in to play and is
dependent on the client IP address (which changes in our scenario).

Many thanks for your help and assistance

Tony Stiles

 

[Robbe Morris [C# MVP]]

I have seen problems with proxy servers before but it didn't
impact our viewstate. Just impacted session.

We purchased ScaleOut StateServer and it works beautifully.

http://www.eggheadcafe.com/articles/scaleout_server.asp