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// Web

Port 11371: OpenPGP HTTP Keyserver

Port 11371 is assigned by IANA to hkp (OpenPGP HTTP Keyserver).

11371

How hkp works

Web
browser:11371hkp browser:11371hkp

A browser sends an HTTP request to port 11371 and the hkp server sends the page back.

Transport
TCP · UDP
Exposure risk
not rated depends on the program listening
Encryption
Unknownnot stated by the registry
IANA status
Assigned1 registered service
Range
Registered (1024-49151)
Category
Web
01 Security

Is port 11371 dangerous?

We have no specific security note for port 11371. Its risk depends on the program actually listening on it. General advice for web services:

  • Serve it over HTTPS only and check the HTTP security headers.
  • Keep admin consoles and development servers off the Internet.
  • Patch the application server and remove default credentials and sample apps.
02 Registry

IANA registry entries for port 11371

ServicePortTransportDescriptionReferenceUpdated
hkp 11371 TCP, UDP OpenPGP HTTP Keyserver - 2003-05

// source: IANA service name and port number registry

03 Check it

Which program uses port 11371, and is it reachable?

Linux

sudo ss -ltnup 'sport = :11371'      # process listening on 11371
sudo lsof -nP -i :11371

macOS

sudo lsof -nP -i :11371

Windows (PowerShell)

Get-NetTCPConnection -LocalPort 11371 -State Listen | Select LocalAddress, OwningProcess
Get-NetUDPEndpoint -LocalPort 11371
netstat -ano | findstr :11371

From another machine

nmap -p 11371 -sV <host>
sudo nmap -sU -p 11371 <host>
nc -zv <host> 11371

Block it in the firewall

sudo ufw deny 11371/tcp                                         # Linux (ufw)
New-NetFirewallRule -DisplayName "Block 11371" -Direction Inbound -LocalPort 11371 -Protocol TCP -Action Block  # Windows
04 FAQ
What is port 11371 used for?

Port 11371 is assigned by IANA to hkp (OpenPGP HTTP Keyserver).

Is port 11371 TCP or UDP?

Port 11371 is registered for TCP and UDP.

Is it safe to open port 11371?

It depends on the program that listens on it. Open it only for a service you know and only to the networks that need it. Serve it over HTTPS only and check the HTTP security headers.

How do I check if port 11371 is open?

On Linux run "ss -ltnup 'sport = :11371'", on macOS "lsof -nP -i :11371", and on Windows "netstat -ano | findstr :11371" to see the local process. From another machine, "nmap -p 11371 <host>" shows whether it is reachable.

05 Related
:443 HTTPS tcp · udp · sctp · low risk :80 HTTP tcp · udp · sctp · moderate risk :8080 HTTP alternate tcp · udp · high risk :8443 HTTPS alternate tcp · udp · moderate risk :3000 Dev servers / Grafana tcp · udp · moderate risk :5000 Flask / Docker registry / UPnP tcp · udp · moderate risk :8000 HTTP alternate (dev) tcp · udp · moderate risk :8888 Jupyter / HTTP alternate tcp · udp · high risk

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