Skip to main content

IPv6-to-IPv4 translation FTP considerations

Document Type Replaced Internet-Draft (individual)
Expired & archived
Author Iljitsch van Beijnum
Last updated 2009-12-21 (Latest revision 2009-10-19)
Replaced by draft-ietf-behave-ftp64
RFC stream (None)
Intended RFC status (None)
Stream Stream state (No stream defined)
Consensus boilerplate Unknown
RFC Editor Note (None)
IESG IESG state Replaced by draft-ietf-behave-ftp64
Telechat date (None)
Responsible AD (None)
Send notices to (None)

This Internet-Draft is no longer active. A copy of the expired Internet-Draft is available in these formats:


The File Transfer Protocol has a very long history, and despite the fact that today, other options exist to perform file transfers, FTP is still in common use. As such, it is important that in the situation where some client computers are IPv6-only while many servers are still IPv4-only and IPv6-to-IPv4 translators are used to bridge that gap, FTP is made to work through these translators as best it can. FTP has an active and a passive mode, both as original commands that are IPv4-specific, and as extended, IP version agnostic commands. The only FTP mode that works without changes through an IPv6-to-IPv4 translator is extended passive. However, many existing FTP servers don't support this mode, and some clients don't ask for it. This document describes server, client and middlebox (if any) behavior that minimizes this problem.


Iljitsch van Beijnum

(Note: The e-mail addresses provided for the authors of this Internet-Draft may no longer be valid.)