1. I'm running DNN 6.00.01 on a virtual server, using a shared MSSQL 2008 host on the backend.  The virtual server is running Windows 2008 R2 Server (64-bit) with 3 GB RAM, single virtual CPU.  I am using a fqdn to connect to the database (with SQL authentication) in the connection string, not an IP address.
   
   
2. This was not a site upgrade, it was a clean install.
   
   
3. The Problem: When the DNN app goes down, I am routed to the UnderConstruction.htm page.  If I explicitly go to the Install.apx?mode=upgrade page, it tells me it is timing out connecting to the database.  But I am certain the SQL server is pingable during this time, and I can connect to it with the admin tool I have to maintain the schema, SSIS jobs, etc etc etc.
   
4. Recycling the app pool at this time does not always fix the problem.  Nor does restarting IIS 7 (iisreset) fix it every time.  It's random.
   
   
5. I am currently using the dbmon at Codeplex, with a 10000 ms interval, and it still happens.  I changed the IIS app pool to only recycle at 1200a instead of every x minutes.  Still no improvement.
   
   
6. The site is not live.  I am the only one using it.
   
   
7. I have ensured I am allowing 32-bit applications in IIS, with Integrated Mode enabled, using the NetworkService as the App Pool identity.  The app pool idle timeout is set to 720, and is using .Net 2.0
   
   
8. I cannot get Wireshark to install, otherwise I would sniff the traffic.  I think it's due to the fact that winpcap isn't somehow happy with Windows 2008 64-bit.

 I have ensured I am allowing 32-bit applications in IIS, with Integrated Mode enabled, using the NetworkService as the App Pool identity.  The app pool idle timeout is set to 720, and is using .Net 2.0

   

 Not sure if this is an issue but I have my app pools set to .net 4.0 for all 6.0 and later sites.