23
Telnet
Critical RiskTCP — Remote Access
Port Overview
Port Number
23
Service Name
Telnet
Transport Protocol
TCP
Category
Remote Access
Security Risk
Critical
Port Range
Well-Known (0-1023)
What is Port 23?
Telnet protocol. Provides unencrypted text-based remote login to network devices and servers. All data including passwords is sent in plaintext.
TCP
Remote Access
Commonly Used
Security Considerations
Port 23 (Telnet) is classified as critical risk. This port should not be exposed to the public internet. The service transmits data without encryption, making it vulnerable to eavesdropping, credential theft, and man-in-the-middle attacks.
Recommendation: Block this port at the firewall. Use encrypted alternatives (SSH, SFTP, HTTPS) instead.