We've been having a lot of funky issues with some of our web based applications that allow clients to submit lot of image files to our servers. Lots of ports are used in the process.
http://www.microsoft.com/technet/security/bulletin/MS09-048.mspx - released in Sept-2009.
support.microsoft.com/kb/974288 - Memory Pressure Protection description.
Evidently, after applying KB967723, our clients receive funky error messages as if connections cannot be made to the server or connections have been closed. There doesn't appear to be a pattern and sometimes it works and other times is doesn't. Typically we've noticed it when server is under load.
I'm curious what others think about this MPP and any issues that you may have experienced from it. I understand its purpose, but I think it may have broken a lot of apps in the process. It doesn't look like Microsoft made this "feature" public to everyone.