Is port 111 (RPCBind / Portmapper) dangerous?

Port 111 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 111 be open on my firewall?

No, port 111 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 111 use?

Port 111 (RPCBind / Portmapper) uses the TCP/UDP transport protocol and falls under the System & Infrastructure category.

:111 (TCP/UDP)

RPCBind / Portmapper

Critical Risk

TCP/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.

Related Ports — System & Infrastructure

0 Reserved 1 TCPMUX 2 Management Utility 3 CompressNET 4 Unassigned 5 RJE 6 Unassigned 7 Echo

Related Terms

Bandwidth Latency Packet Loss Ping Throughput ASN