513
rlogin
Critical RiskTCP — Remote Access
Port Overview
Port Number
513
Service Name
rlogin
Transport Protocol
TCP
Category
Remote Access
Security Risk
Critical
Port Range
Well-Known (0-1023)
What is Port 513?
Port 513 is assigned to rlogin, which relies on a deeply flawed IP-based trust model with no encryption. Critical security vulnerability.
TCP
Remote Access
Security Considerations
Port 513 (rlogin) 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.