543
Kerberos Login
High RiskTCP — Remote Access
Port Overview
Port Number
543
Service Name
Kerberos Login
Transport Protocol
TCP
Category
Remote Access
Security Risk
High
Port Range
Well-Known (0-1023)
What is Port 543?
Port 543 is assigned to klogin, the Kerberos-authenticated rlogin service. Superseded by Kerberos-authenticated SSH.
TCP
Remote Access
Security Considerations
Port 543 (Kerberos Login) is classified as high risk. This port is a common target for automated scanning and brute-force attacks. If you must expose it, restrict access to known IP addresses.
Recommendation: Use firewall rules to whitelist trusted IPs. Enable rate limiting and intrusion detection.