RFC 1123 · INTERNET STANDARD · 1989
MON · 27 JUL 2026
Requirements for Internet Hosts - Application and Support
Overview
RFC 1123, “Requirements for Internet Hosts - Application and Support”, is an Internet Standard document published in October 1989 by R. Braden. It updates RFC 822, RFC 952. It has since been updated by RFC 1349, RFC 2181, RFC 5321, RFC 5966, RFC 7766, RFC 9210. The canonical text is published by the RFC Editor.
Abstract
This RFC is an official specification for the Internet community. It incorporates by reference, amends, corrects, and supplements the primary protocol standards documents relating to hosts. [STANDARDS-TRACK]
What “Internet Standard” means
A mature, widely-implemented specification that has completed the full IETF standards process — the highest maturity level on the standards track.
Read this RFC
The canonical text of RFC 1123 is hosted at rfc-editor.org. Available in TXT,HTML.
Relationships to other RFCs
Other RFCs from 1989
- RFC 1122 Requirements for Internet Hosts - Communication Layers
- RFC 1124 Policy issues in interconnecting networks
- RFC 1121 Act one - the poems
- RFC 1125 Policy requirements for inter Administrative Domain routing
- RFC 1120 Internet Activities Board
- RFC 1126 Goals and functional requirements for inter-autonomous system routing
- RFC 1119 Network Time Protocol specification and implementation
- RFC 1127 Perspective on the Host Requirements RFCs