Status of TCP connections (classic)

The status of a TCP connection can be one of the following:

established
The remote party has accepted the TCP connection and it is still active.

closed
The system closed the TCP connection after it was successfully established.

no service
The remote party acknowledged the initial SYN message by an RST message, for example the remote party does exist, but no service is bound to the request port. Most personal computers are protected by a firewall that discards RST messages to prevent effective port scanning.

no host
The remote party does not acknowledge the SYN message, for example, the remote party does not exist or it is protected by a firewall.

rejected
The operating system itself rejected the TCP connection, possibly due to security settings.