Transmission Control Protocol (TCP)
This specification has been revised 17 times since RFC 675 (1974). Each document below formally obsoleted the one before it; the versions still in force are listed first.
Revision timeline
Current versions — implement against these
Superseded versions — historical reference only
- RFC 675Specification of Internet Transmission Control ProgramObsoletedDecember 1974historicreplaced by RFC7805
- RFC 721Out-of-Band Control Signals in a Host-to-Host ProtocolObsoletedSeptember 1976historicreplaced by RFC7805
- RFC 761DoD standard Transmission Control ProtocolObsoletedJanuary 1980historicreplaced by RFC793, RFC7805
- RFC 793Transmission Control ProtocolObsoletedSeptember 1981internet standardreplaced by RFC9293
- RFC 813Window and Acknowledgement Strategy in TCPObsoletedJuly 1982historicreplaced by RFC7805
- RFC 816Fault isolation and recoveryObsoletedJuly 1982historicreplaced by RFC7805
- RFC 879The TCP Maximum Segment Size and Related TopicsObsoletedNovember 1983historicreplaced by RFC7805, RFC9293
- RFC 896Congestion Control in IP/TCP InternetworksObsoletedJanuary 1984historicreplaced by RFC7805
- RFC 1078TCP port service Multiplexer (TCPMUX)ObsoletedNovember 1988historicreplaced by RFC7805
- RFC 1948Defending Against Sequence Number AttacksObsoletedMay 1996informationalreplaced by RFC6528
- RFC 2873TCP Processing of the IPv4 Precedence FieldObsoletedJune 2000proposed standardreplaced by RFC9293
- RFC 6013TCP Cookie Transactions (TCPCT)ObsoletedJanuary 2011historicreplaced by RFC7805
- RFC 6093On the Implementation of the TCP Urgent MechanismObsoletedJanuary 2011proposed standardreplaced by RFC9293
- RFC 6429TCP Sender Clarification for Persist ConditionObsoletedDecember 2011informationalreplaced by RFC9293
- RFC 6528Defending against Sequence Number AttacksObsoletedFebruary 2012proposed standardreplaced by RFC9293
- RFC 6691TCP Options and Maximum Segment Size (MSS)ObsoletedJuly 2012informationalreplaced by RFC9293
This lineage is derived automatically from the “obsoletes” relationships recorded in the public RFC Editor index — no editorial judgement is applied to the ordering. The most recent document in the chain is RFC 9293 (August 2022).