Which TCP state is defined by proto_state=04?

The TCP state defined by proto_state=04 is associated with the FIN_WAIT state, which indicates that the connection is in the process of being terminated. When a TCP connection is closing, one side sends a FIN packet to signal that it has finished sending data. If the other side acknowledges this FIN packet, the connection moves into the FIN_WAIT state as it awaits either the acknowledgment of its own FIN packet or for additional data from the other side before completely closing down.

In the context of TCP connections, different states represent various stages in the connection lifecycle, and FIN_WAIT specifically indicates that the endpoint is waiting for further closure communications, marking it as a transitional state during the end of a session. Understanding this helps clarify the role of TCP states in managing network connections effectively during their lifecycle.