Windows 2003 & .NET Remoting, CruiseControl.NET, SVN, Freezes, Lockups, and Stalls with localhost - ZoneAlarm at Fault

I’ve been having a problem on my servers for a few months now that would occasionally “creep up” from time to time.  Applications would freeze up running after running a .NET application that uses .NET remoting (like CuriseControl.NET).  Other times, I’ve had SVN.exe (Win32 build) lockup when connecting to localhost.  The problem I was having went something like this:

• I would start an application that connected to localhost.
• The application would attempt to make a connection to localhost.
• TcpView would show the connection being made and established.
• Once the application established a connection on localhost, all Operating System functions would come to a grinding halt.  Any attempt to launch any new processes would fail.  For example, if I started notepad from Start>Run… explorer would have accepted the command and the run box would have dissapeared, only that it seemed like the application launch was “queued”.  Notepad would not run until I closed the connection that was being made in TCPView.

Really weird behavior, until I started uninstalling things from the server one by one.  My first target was the JAVA6 runtime, my second target was ZoneAlarm.  After I uninstalled ZoneAlarm 6.5.737.000, everything started working beautifully.  Now, I bet CurseControl.NET will work. :)

If you ever have problems with the operating system locking up when an application attempts to connect to localhost and you have ZoneAlarm installed, good chances are, ZoneAlarm (with its drivers working in kernel mode) are the root cause of the problem.