Q & A on Rebooting and TCP connections Q: Two computers are connected on internet using TCP. Suddenly one of the computers gets rebooted. it takes 30 seconds to come up again. How can the other computer know that the connection is half open. A: There are two possibilities. (1) the application on the live computer attempts to send data while the peer is down. TCP will attempt to retransmit. Eventually, when the peer boots, it will sent a RESET, closing the connection. (2) the application on the live computer does not send data. In this case, it cannot know that the peer has been rebooted.