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// Other services

Port 3927: ScsTsr

Port 3927 is assigned by IANA to natdataservice (ScsTsr).

3927

How natdataservice works

Other services
client:3927natdataserviceresponse client:3927natdataserviceresponse

The client sends a request to port 3927 and the natdataservice 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 3927 dangerous?

We have no specific security note for port 3927. 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 3927

ServicePortTransportDescriptionReferenceUpdated
natdataservice 3927 TCP, UDP ScsTsr - 2003-11

// source: IANA service name and port number registry

03 Check it

Which program uses port 3927, and is it reachable?

Linux

sudo ss -ltnup 'sport = :3927'      # process listening on 3927
sudo lsof -nP -i :3927

macOS

sudo lsof -nP -i :3927

Windows (PowerShell)

Get-NetTCPConnection -LocalPort 3927 -State Listen | Select LocalAddress, OwningProcess
Get-NetUDPEndpoint -LocalPort 3927
netstat -ano | findstr :3927

From another machine

nmap -p 3927 -sV <host>
sudo nmap -sU -p 3927 <host>
nc -zv <host> 3927

Block it in the firewall

sudo ufw deny 3927/tcp                                         # Linux (ufw)
New-NetFirewallRule -DisplayName "Block 3927" -Direction Inbound -LocalPort 3927 -Protocol TCP -Action Block  # Windows
04 FAQ
What is port 3927 used for?

Port 3927 is assigned by IANA to natdataservice (ScsTsr).

Is port 3927 TCP or UDP?

Port 3927 is registered for TCP and UDP.

Is it safe to open port 3927?

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 3927 is open?

On Linux run "ss -ltnup 'sport = :3927'", on macOS "lsof -nP -i :3927", and on Windows "netstat -ano | findstr :3927" to see the local process. From another machine, "nmap -p 3927 <host>" shows whether it is reachable.

05 Related
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