Connection Termination

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Graceful connection close using a four-way handshake: initiator sends FIN, receiver ACKs, receiver sends FIN, initiator ACKs. The initiator enters TIME_WAIT state for 2*MSL (typically 60 seconds) to handle delayed packets. Lingering sockets in TIME_WAIT can exhaust port space on busy servers.

Key Properties

• FIN Handshake
• TIME_WAIT State
• Lingering Sockets

Related

• Three-Way Handshake (opening the connection)
• Keep-Alive (avoiding connection teardown/setup overhead)

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networking tcp