Running P2P applications in Vista and ever see this message coming up? In your event viewer, the exact wording is ‘TCP/IP has reached the security limit imposed on the number of concurrent TCP connect attempts’.
Microsoft has implemented a change in the TCP/IP stack since XP SP2 to limit the number of ‘half-open’ (incomplete/syn packets) connection attempts per second to keep your computer from being used by dangerous programs such as worms that scan the internet to infect more systems.
I stumbled on this feature(?) only today as I don’t use Vista. Fortunately, if your P2P applications are suffering, there is a patch. You can download it from here.