Port
Port 21 — FTP control
Port 21 (TCP) is used by FTP control. File Transfer Protocol command/control channel — logins and commands.
Port 21 at a glance
| Property | Value |
|---|---|
| Port number | 21 |
| Transport | TCP |
| Service | FTP control |
| Category | Well-known port |
What it is used for
File Transfer Protocol command/control channel — logins and commands.
Security considerations
Clear text logins. Replace with SFTP (SSH) where possible.
See our full TCP/UDP port reference and learn how firewalls filter ports in the CyberOps course.
Frequently asked questions
What is port 21 used for?
Port 21 (TCP) is used by FTP control. File Transfer Protocol command/control channel — logins and commands.
Is port 21 TCP or UDP?
Port 21 uses TCP.
Is it safe to open port 21?
Clear text logins. Replace with SFTP (SSH) where possible.
Related
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