RFC 640 · UNKNOWN · 1974
WED · 29 JUL 2026
Revised FTP reply codes
Overview
RFC 640, “Revised FTP reply codes”, is an Unknown document published in June 1974 by J. Postel. It updates RFC 542. The canonical text is published by the RFC Editor.
Abstract
Updates RFC 542.
What “Unknown” means
The standards-track status of this early RFC was never formally classified.
Read this RFC
The canonical text of RFC 640 is hosted at rfc-editor.org. Available in TXT,HTML.
Relationships to other RFCs
Other RFCs from 1974
- RFC 638 IMP/TIP preventive maintenance schedule
- RFC 642 Ready line philosophy and implementation
- RFC 637 Change of network address for SU-DSL
- RFC 643 Network Debugging Protocol
- RFC 636 TIP/Tenex reliability improvements
- RFC 644 On the problem of signature authentication for network mail
- RFC 635 Assessment of ARPANET protocols
- RFC 645 Network Standard Data Specification syntax