111
RPCBind / Portmapper
Critical RiskTCP/UDP — System & Infrastructure
Port Overview
Port Number
111
Service Name
RPCBind / Portmapper
Transport Protocol
TCP/UDP
Category
System & Infrastructure
Security Risk
Critical
Port Range
Well-Known (0-1023)
What is Port 111?
RPCBind (also called portmapper) maps ONC RPC program numbers to the dynamic ports on which those services are listening. Exposing port 111 on the internet is a well-known critical vulnerability.
TCP/UDP
System & Infrastructure
Commonly Used
Security Considerations
Port 111 (RPCBind / Portmapper) 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.