CyberHunter
// Other services

Port 5166: WinPCS Service Connection

Port 5166 is assigned by IANA to winpcs (WinPCS Service Connection).

5166

How winpcs works

Other services
client:5166winpcsresponse client:5166winpcsresponse

The client sends a request to port 5166 and the winpcs 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)
01 Security

Is port 5166 dangerous?

We have no specific security note for port 5166. 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 5166

ServicePortTransportDescriptionReferenceUpdated
winpcs 5166 TCP, UDP WinPCS Service Connection - 2006-02

// source: IANA service name and port number registry

03 Check it

Which program uses port 5166, and is it reachable?

Linux

sudo ss -ltnup 'sport = :5166'      # process listening on 5166
sudo lsof -nP -i :5166

macOS

sudo lsof -nP -i :5166

Windows (PowerShell)

Get-NetTCPConnection -LocalPort 5166 -State Listen | Select LocalAddress, OwningProcess
Get-NetUDPEndpoint -LocalPort 5166
netstat -ano | findstr :5166

From another machine

nmap -p 5166 -sV <host>
sudo nmap -sU -p 5166 <host>
nc -zv <host> 5166

Block it in the firewall

sudo ufw deny 5166/tcp                                         # Linux (ufw)
New-NetFirewallRule -DisplayName "Block 5166" -Direction Inbound -LocalPort 5166 -Protocol TCP -Action Block  # Windows
04 FAQ
What is port 5166 used for?

Port 5166 is assigned by IANA to winpcs (WinPCS Service Connection).

Is port 5166 TCP or UDP?

Port 5166 is registered for TCP and UDP.

Is it safe to open port 5166?

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 5166 is open?

On Linux run "ss -ltnup 'sport = :5166'", on macOS "lsof -nP -i :5166", and on Windows "netstat -ano | findstr :5166" to see the local process. From another machine, "nmap -p 5166 <host>" shows whether it is reachable.

05 Related