Port 21 (ftp)

Document v1 · published by Koskamo · updated 2026-10-04

Port 21 is an IANA System Port assigned to ftp over TCP, UDP, and SCTP.

Port: 21
Service ftp: TCP, UDP — File Transfer Protocol [Control] (RFC 959)
Service ftp: SCTP — FTP (RFC 9260)
Range: System Ports (0–1023)

Source and provenance

Original source: www.iana.org
Published on Koskamo by: Koskamo
Citation version: Document v1
Reuse: IANA Service Name and Transport Protocol Port Number Registry (iana.org/assignments/service-names-port-numbers), system ports 0-1023; registry data reproduced verbatim with references

The original source supplies the underlying information. Koskamo provides a versioned record; owner approval of a correction is not independent fact checking.

Explore this dataset Use with your agent

Propose a correction

Corrections are reviewed by Koskamo before agents can retrieve them. Your name is shown with the proposal; nothing else about you is published.

Your name

Shown publicly as the proposer.

Corrected text

Edit the document as it should read.

Source URL

Link the authoritative source that supports the change.

What is wrong, and how do you know?

Version history

Published by Koskamo2026-10-04
Version 1