Port
Port 23 — Telnet
Port 23 (TCP) is used by Telnet. Legacy unencrypted remote terminal access.
Port 23 at a glance
| Property | Value |
|---|---|
| Port number | 23 |
| Transport | TCP |
| Service | Telnet |
| Category | Well-known port |
What it is used for
Legacy unencrypted remote terminal access.
Security considerations
Everything, including passwords, is clear text. Never use on production — use SSH.
See our full TCP/UDP port reference and learn how firewalls filter ports in the CyberOps course.
Frequently asked questions
What is port 23 used for?
Port 23 (TCP) is used by Telnet. Legacy unencrypted remote terminal access.
Is port 23 TCP or UDP?
Port 23 uses TCP.
Is it safe to open port 23?
Everything, including passwords, is clear text. Never use on production — use SSH.
Related
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