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// Other services

Port 6503: BoKS Clntd

Port 6503 is assigned by IANA to boks_clntd (BoKS Clntd), boks-clntd (BoKS Clntd IANA assigned this well-formed service name as a replacement for "boks_clntd".).

6503

How boks_clntd works

Other services
client:6503boks_clntdresponse client:6503boks_clntdresponse

The client sends a request to port 6503 and the boks_clntd service answers.

Transport
TCP · UDP
Exposure risk
not rated depends on the program listening
Encryption
Unknownnot stated by the registry
IANA status
Assigned2 registered services
Range
Registered (1024-49151)
Category
Other services
01 Security

Is port 6503 dangerous?

We have no specific security note for port 6503. 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 6503

ServicePortTransportDescriptionReferenceUpdated
boks_clntd 6503 TCP, UDP BoKS Clntd - -
boks-clntd 6503 TCP, UDP BoKS Clntd IANA assigned this well-formed service name as a replacement for "boks_clntd". - -

// source: IANA service name and port number registry

03 Check it

Which program uses port 6503, and is it reachable?

Linux

sudo ss -ltnup 'sport = :6503'      # process listening on 6503
sudo lsof -nP -i :6503

macOS

sudo lsof -nP -i :6503

Windows (PowerShell)

Get-NetTCPConnection -LocalPort 6503 -State Listen | Select LocalAddress, OwningProcess
Get-NetUDPEndpoint -LocalPort 6503
netstat -ano | findstr :6503

From another machine

nmap -p 6503 -sV <host>
sudo nmap -sU -p 6503 <host>
nc -zv <host> 6503

Block it in the firewall

sudo ufw deny 6503/tcp                                         # Linux (ufw)
New-NetFirewallRule -DisplayName "Block 6503" -Direction Inbound -LocalPort 6503 -Protocol TCP -Action Block  # Windows
04 FAQ
What is port 6503 used for?

Port 6503 is assigned by IANA to boks_clntd (BoKS Clntd), boks-clntd (BoKS Clntd IANA assigned this well-formed service name as a replacement for "boks_clntd".).

Is port 6503 TCP or UDP?

Port 6503 is registered for TCP and UDP.

Is it safe to open port 6503?

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 6503 is open?

On Linux run "ss -ltnup 'sport = :6503'", on macOS "lsof -nP -i :6503", and on Windows "netstat -ano | findstr :6503" to see the local process. From another machine, "nmap -p 6503 <host>" shows whether it is reachable.

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