Concepts / Network services

Network services

HTTP keep-alive

Also called persistent connection, Connection: close, connection reuse

Several HTTP requests over one TCP connection instead of a new handshake for each.

HTTP/1.1 keeps the connection open after a response by default, so the next request skips the TCP handshake (and, over HTTPS, the TLS one). The client finds where each response ends from its Content-Length (or chunked encoding). Connection: close asks the server to hang up after answering, as HTTP/1.0 did: one handshake per request. The server closes idle connections after a timeout.

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