On my Win7 workstation, when a program initiates a network connection, it hangs for exactly 31 seconds (I wrote a test application to investigate this). It will eventually get established and the program will work fine from then on until its closed. Also, after initiating its first network connection, all subsequent connections are allowed without a pause.
This does not apply to ICMP pings. My test app can ping a computer without a pause, then initiate an HTTP connection to a server and hang for 30 seconds.
The issue is specific to each process. I can have multiple instances of the same process connecting to the same computer and each one will exhibit the behavior on their initial connection.
This also isn't a hardware issue. Its something in Windows install's networking stack. I have VMware on this machine and inside a VM, I can initiate connections without the pause.
Also, I've run Wireshark and I don't see any packets (SYN or anything) until after the 31 seconds.
I've looked at Windows Firewall and its disabled. Does this sound familiar to anyone? Does anyone have any ideas on where I can look?