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// Other services

Port 3739: Launchbird LicenseManager

Port 3739 is assigned by IANA to launchbird-lm (Launchbird LicenseManager).

3739

How launchbird-lm works

Other services
client:3739launchbird-lmresponse client:3739launchbird-lmresponse

The client sends a request to port 3739 and the launchbird-lm 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 3739 dangerous?

We have no specific security note for port 3739. 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 3739

ServicePortTransportDescriptionReferenceUpdated
launchbird-lm 3739 TCP, UDP Launchbird LicenseManager - 2003-04

// source: IANA service name and port number registry

03 Check it

Which program uses port 3739, and is it reachable?

Linux

sudo ss -ltnup 'sport = :3739'      # process listening on 3739
sudo lsof -nP -i :3739

macOS

sudo lsof -nP -i :3739

Windows (PowerShell)

Get-NetTCPConnection -LocalPort 3739 -State Listen | Select LocalAddress, OwningProcess
Get-NetUDPEndpoint -LocalPort 3739
netstat -ano | findstr :3739

From another machine

nmap -p 3739 -sV <host>
sudo nmap -sU -p 3739 <host>
nc -zv <host> 3739

Block it in the firewall

sudo ufw deny 3739/tcp                                         # Linux (ufw)
New-NetFirewallRule -DisplayName "Block 3739" -Direction Inbound -LocalPort 3739 -Protocol TCP -Action Block  # Windows
04 FAQ
What is port 3739 used for?

Port 3739 is assigned by IANA to launchbird-lm (Launchbird LicenseManager).

Is port 3739 TCP or UDP?

Port 3739 is registered for TCP and UDP.

Is it safe to open port 3739?

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 3739 is open?

On Linux run "ss -ltnup 'sport = :3739'", on macOS "lsof -nP -i :3739", and on Windows "netstat -ano | findstr :3739" to see the local process. From another machine, "nmap -p 3739 <host>" shows whether it is reachable.

05 Related
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