@TP-Link Some SSH servers, for example, are configured to use IDENT to obtain the username of the client initiating the connection. If the router does not open port 113 back to the client when a new, outgoing SSH connection is made then there is a delay of several seconds while the SSH server waits for the IDENT request to time out since, in my experience, routers will simply not respond to connections if there is no open port.