André Krijnen

After a hard day with some errors failing a production server at a customer I had to find out what caused all these troubles… Well I had alot of messages in the Application Log with the messages ViewState verification failed… what’s causing all these messages? Well I had to find it out… So after some research it could be alot of things that causing these messages, but I couldn’t find out which one it was…

Till I found another error message in the System Log… these messages caused a Deadlock on the Thread, and if this happens IIS will create a new Thread that will continue, but after 20 deadlocks IIS went down… hmm odd, so I found out that this came from the application. And it came from the System.Diagnostics.Debug.Assert, but huh, I thought that I had delivered a Release version. Well maybe, maybe not. So I knew for some reason this was causing all these messages.

Well I thought that I could kill these messages by setting debug=”false”, well I can assure you, that won’t work. I had that figured out the next day, when the Administrator called me that the production server went down every 5 to 10 minutes… hmm so I called Edward Bakker, and asked him if he had a solution. After some talking with each other and Internet by hand I searched and came out by the blog of Scott Hanselman. And he had the solution for my problem.

This problem can cause severe damage and it seems to be a bug in ASP.NET 2.0… Thanks to Scott and Edward I managed to figure it out.

Link to blogpost by Scott Hanselman: http://www.hanselman.com/blog/PreventingDialogsOnTheServerSideInASPNETOrTraceFailConsideredHarmful.aspx

The last couple of days I was working at a customer where Kerberos was needed for SharePoint 2010. Of course I started to set the different Service Principal Names for my App Pool accounts, farm accounts, machines, etc. Not to hard to do it, but I ran everytime in a 401 error: The requsted resources requires user authentication.
Strange I thought, but yet I sended the Domain Administrator more commando’s and it didn’t help. So I checked everything, checked for duplicates, etc. Still I ran into these errors.

After some search I found out that there are some problems with IIS 7.0 regarding Kerberos, and I needed to configure the applicationHost.config to solve these issues with Kerberos. enabled the kernel activation mode, etc. But, it didn’t make any difference, rebooted several times, removed the Kernel Activation Mode and removed again the changed on the applicationHost.config.

I knew that we’ve made C-Name records and it gave me a wonderfull idea to change the C-Name records to A records. These changes where applied, and wow, in less time as expected I opened IE and opened the different web apps. In less then a second the page was displayed from my web app. When you run in these problems, change your C-Name record to A-record and it will fix all your problems with SPN’s, Kerberos and IIS 7.0

A strange thing happend last day is that for some reason my Web Server went down in action… I couldn’t explain why it happend, but I managed to gave it a rebirth of the server.

After 30 days without reboot, wow :-S It went down, and yet I cannot figure out why. Nothing changed, and I saw my logfiles and even there it didn’t show anything. So, what happened then? I don’t know.