CyberHunter
Local dataset, no network
// Other services

Port 4166: Joost Peer to Peer Protocol

Port 4166 is assigned by IANA to joost (Joost Peer to Peer Protocol).

4166

How joost works

Other services
client:4166joostresponse client:4166joostresponse

The client sends a request to port 4166 and the joost 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 4166 dangerous?

We have no specific security note for port 4166. 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 4166

ServicePortTransportDescriptionReferenceUpdated
joost 4166 TCP, UDP Joost Peer to Peer Protocol - 2007-04

// source: IANA service name and port number registry

03 Check it

Which program uses port 4166, and is it reachable?

Linux

sudo ss -ltnup 'sport = :4166'      # process listening on 4166
sudo lsof -nP -i :4166

macOS

sudo lsof -nP -i :4166

Windows (PowerShell)

Get-NetTCPConnection -LocalPort 4166 -State Listen | Select LocalAddress, OwningProcess
Get-NetUDPEndpoint -LocalPort 4166
netstat -ano | findstr :4166

From another machine

nmap -p 4166 -sV <host>
sudo nmap -sU -p 4166 <host>
nc -zv <host> 4166

Block it in the firewall

sudo ufw deny 4166/tcp                                         # Linux (ufw)
New-NetFirewallRule -DisplayName "Block 4166" -Direction Inbound -LocalPort 4166 -Protocol TCP -Action Block  # Windows
04 FAQ
What is port 4166 used for?

Port 4166 is assigned by IANA to joost (Joost Peer to Peer Protocol).

Is port 4166 TCP or UDP?

Port 4166 is registered for TCP and UDP.

Is it safe to open port 4166?

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 4166 is open?

On Linux run "ss -ltnup 'sport = :4166'", on macOS "lsof -nP -i :4166", and on Windows "netstat -ano | findstr :4166" to see the local process. From another machine, "nmap -p 4166 <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

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