RFC 661 · UNKNOWN · 1974
MON · 15 JUN 2026
Protocol information
Overview
RFC 661, “Protocol information”, is an Unknown document published in November 1974 by J. Postel. It has since been updated by RFC 694. The canonical text is published by the RFC Editor.
Abstract
An old version; see RFC 694.
What “Unknown” means
The standards-track status of this early RFC was never formally classified.
Read this RFC
The canonical text of RFC 661 is hosted at rfc-editor.org. Available in TXT,PDF,HTML.
Relationships to other RFCs
Other RFCs from 1974
- RFC 660 Some changes to the IMP and the IMP/Host interface
- RFC 662 Performance improvement in ARPANET file transfers from Multics
- RFC 659 Announcing additional Telnet options
- RFC 663 Lost message detection and recovery protocol
- RFC 658 Telnet output linefeed disposition
- RFC 657 Telnet output vertical tab disposition option
- RFC 656 Telnet output vertical tabstops option
- RFC 666 Specification of the Unified User-Level Protocol