Is port 751 (Kerberos Master) dangerous?

Port 751 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 751 be open on my firewall?

No, port 751 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 751 use?

Port 751 (Kerberos Master) uses the TCP/UDP transport protocol and falls under the Security & VPN category.

:751 (TCP/UDP)

Kerberos Master

Critical Risk

TCP/UDP — Security & VPN

Port Overview

Port Number 751

Service Name Kerberos Master

Transport Protocol TCP/UDP

Category Security & VPN

Security Risk Critical

Port Range Well-Known (0-1023)

What is Port 751?

Kerberos v4 master database administration service. Relies on cryptographically broken DES encryption. Should be disabled in all environments.

TCP/UDP Security & VPN

Security Considerations

Port 751 (Kerberos Master) 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 — Security & VPN

31 MSG-AUTH 48 Auditd 49 TACACS 56 XNS-AUTH 62 ACA Services 65 TACACS-DS 88 Kerberos 90 DNSIX Security

Related Terms

SSL/TLS Certificate DDoS DNS Spoofing Encryption Firewall HTTPS