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// Other services

Port 5351: Port Control Protocol

Port 5351 is assigned by IANA to pcp (Port Control Protocol).

5351

How pcp works

Other services
client:5351pcpresponse client:5351pcpresponse

The client sends a request to port 5351 and the pcp service answers.

Transport
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 5351 dangerous?

We have no specific security note for port 5351. 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 5351

ServicePortTransportDescriptionReferenceUpdated
pcp 5351 UDP Port Control Protocol RFC 6887 -
-5351-Reserved--

// source: IANA service name and port number registry

03 Check it

Which program uses port 5351, and is it reachable?

Linux

sudo ss -ltnup 'sport = :5351'      # process listening on 5351
sudo lsof -nP -i :5351

macOS

sudo lsof -nP -i :5351

Windows (PowerShell)

Get-NetTCPConnection -LocalPort 5351 -State Listen | Select LocalAddress, OwningProcess
Get-NetUDPEndpoint -LocalPort 5351
netstat -ano | findstr :5351

From another machine

nmap -p 5351 -sV <host>
sudo nmap -sU -p 5351 <host>
nc -zv <host> 5351

Block it in the firewall

sudo ufw deny 5351/udp                                         # Linux (ufw)
New-NetFirewallRule -DisplayName "Block 5351" -Direction Inbound -LocalPort 5351 -Protocol UDP -Action Block  # Windows
04 FAQ
What is port 5351 used for?

Port 5351 is assigned by IANA to pcp (Port Control Protocol).

Is port 5351 TCP or UDP?

Port 5351 is registered for UDP.

Is it safe to open port 5351?

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 5351 is open?

On Linux run "ss -ltnup 'sport = :5351'", on macOS "lsof -nP -i :5351", and on Windows "netstat -ano | findstr :5351" to see the local process. From another machine, "nmap -p 5351 <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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