CyberHunter
LinkedIn profile - Bastien Cordier Email: contact@bastiencordier.pro
// Other services

Port 2931: Circle-X

Port 2931 is assigned by IANA to circle-x (Circle-X).

2931

How circle-x works

Other services
client:2931circle-xresponse client:2931circle-xresponse

The client sends a request to port 2931 and the circle-x service answers.

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
Other services
01 Security

Is port 2931 dangerous?

We have no specific security note for port 2931. Its risk depends on the program actually listening on it. General advice for other services services:

  • Close the port if nothing on the host needs it.
  • Identify the process that listens on it (commands below) before opening it in a firewall.
  • Expose a service only to the networks that use it.
02 Registry

IANA registry entries for port 2931

ServicePortTransportDescriptionReferenceUpdated
circle-x 2931 TCP, UDP Circle-X - -

// source: IANA service name and port number registry

03 Check it

Which program uses port 2931, and is it reachable?

Linux

sudo ss -ltnup 'sport = :2931'      # process listening on 2931
sudo lsof -nP -i :2931

macOS

sudo lsof -nP -i :2931

Windows (PowerShell)

Get-NetTCPConnection -LocalPort 2931 -State Listen | Select LocalAddress, OwningProcess
Get-NetUDPEndpoint -LocalPort 2931
netstat -ano | findstr :2931

From another machine

nmap -p 2931 -sV <host>
sudo nmap -sU -p 2931 <host>
nc -zv <host> 2931

Block it in the firewall

sudo ufw deny 2931/tcp                                         # Linux (ufw)
New-NetFirewallRule -DisplayName "Block 2931" -Direction Inbound -LocalPort 2931 -Protocol TCP -Action Block  # Windows
04 FAQ
What is port 2931 used for?

Port 2931 is assigned by IANA to circle-x (Circle-X).

Is port 2931 TCP or UDP?

Port 2931 is registered for TCP and UDP.

Is it safe to open port 2931?

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. Close the port if nothing on the host needs it.

How do I check if port 2931 is open?

On Linux run "ss -ltnup 'sport = :2931'", on macOS "lsof -nP -i :2931", and on Windows "netstat -ano | findstr :2931" to see the local process. From another machine, "nmap -p 2931 <host>" shows whether it is reachable.

05 Related
:4444 Metasploit default / krb524 tcp · udp · high risk :31337 Back Orifice / elite tcp · udp · high risk :1 TCP Port Service Multiplexer tcp · udp :5 Remote Job Entry tcp · udp :9 Discard tcp · udp · sctp · dccp :11 Active Users tcp · udp :17 Quote of the Day tcp · udp :18 Message Send Protocol (historic) tcp · udp

Latest vulnerability news

All news