I've been writing on this TCP server the last few days to integrate our software with some services used by the rest of the company.
Noticed the company service keeps making a new connection for every single message, and closes this at client side (without signifying the server).

So I contact the team who wrote these services and ask them what's happening. Team lead of that team doubts that I know what I'm talking about and tells me TCP automagically signals the server on disconnect, and this probably is a .Net only problem.

5 seconds of googlefu: half open tcp connection.

Apparently, the application doesn't care about dropped connections and losing connection states even though every service should be checked for licensing when connecting to the server. With this set-up everyone can just send a message other than the registration and pass through any 'validation' due to the fact there can be no connection state.

F*CKING INEPT IDIOT(S) OF TEAM LEAD/DEVELOPER TEAM!