The Registry parameter TcpMaxConnectRetransmissions determines the number of times TCP retransmits a connect request (a SYN) before aborting the attempt. The retransmission time-out is doubled with each successive retransmission in a given connect attempt. The initial time-out value is 3 seconds.
Increasing the default value may allow a client to connect over a slow WAN. However, the value should only be changed in very small increments because the time-out value doubles after each transmission retry. Too large a value could ensure that a connection attempt never times out.