Is port 513 (rlogin) dangerous?

Port 513 is classified as critical risk and should not be exposed to the public internet. It transmits data without encryption, making it vulnerable to eavesdropping and credential theft.

Should port 513 be open on my firewall?

No, port 513 should not be open to the public internet. Block it at the firewall and use encrypted alternatives such as SSH, SFTP, or HTTPS instead.

What transport protocol does port 513 use?

Port 513 (rlogin) uses the TCP transport protocol and falls under the Remote Access category.

:513 (TCP)

rlogin

Critical Risk

TCP — 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.

Related Ports — Remote Access

22 SSH 23 Telnet 57 Private Terminal Access 89 SU/MIT Telnet Gateway 95 SUPDUP 107 Remote Telnet 177 XDMCP 219 Uarps

Related Terms

SSL/TLS Certificate DDoS DNS Spoofing Encryption Firewall HTTPS