Problems Balancing IIS servers with ACEs.

Question

Hi ...
Pls your help in this case ...
I just configured an ACE solution for Web Balancing.  The Web Servers are Microsoft Windows 2008 IIS.
The ACE is configured with two contexts, one for Web Servers and other for Application Servers (both in Microsoft solution).
The context were configured in "One Arm" for each subnet (web and apps).
In attached files I'm sending the configuration of ACE. 
Any sugestion ?
The error we got in the browsing is:
System.Web.HttpException: Validation of viewstate MAC failed. If this application is hosted by a Web Farm or cluster, ensure that <machineKey> configuration specifies the same validationKey and validation algorithm. AutoGenerate cannot be used in a cluster.
Invalid viewstate.   Client IP: 10.11.60.26  Port: 1173.

Answer 1

Hello,
Have you checked if your application requires persistence? Even when both server may have the exact same content if the user gets rebalanced to a different server during the connection will fail and that error you're getting could be a probe of it.
Just to confirm try doing a no inservice under the secondary server in the serverfarm in question, clear all the caches and re-test.
If this indeed solves the issue then it can be easily solved using a sticky method such as source IP or cookie insertion.
HTH
Pablo