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// Other services

Port 744: Flexible License Manager

Port 744 is assigned by IANA to flexlm (Flexible License Manager).

744

How flexlm works

Other services
client:744flexlmresponse client:744flexlmresponse

The client sends a request to port 744 and the flexlm 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
Well-known (0-1023)
Category
Other services
01 Security

Is port 744 dangerous?

We have no specific security note for port 744. 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 744

ServicePortTransportDescriptionReferenceUpdated
flexlm 744 TCP, UDP Flexible License Manager - -

// source: IANA service name and port number registry

03 Check it

Which program uses port 744, and is it reachable?

Linux

sudo ss -ltnup 'sport = :744'      # process listening on 744
sudo lsof -nP -i :744

macOS

sudo lsof -nP -i :744

Windows (PowerShell)

Get-NetTCPConnection -LocalPort 744 -State Listen | Select LocalAddress, OwningProcess
Get-NetUDPEndpoint -LocalPort 744
netstat -ano | findstr :744

From another machine

nmap -p 744 -sV <host>
sudo nmap -sU -p 744 <host>
nc -zv <host> 744

Block it in the firewall

sudo ufw deny 744/tcp                                         # Linux (ufw)
New-NetFirewallRule -DisplayName "Block 744" -Direction Inbound -LocalPort 744 -Protocol TCP -Action Block  # Windows
04 FAQ
What is port 744 used for?

Port 744 is assigned by IANA to flexlm (Flexible License Manager).

Is port 744 TCP or UDP?

Port 744 is registered for TCP and UDP.

Is it safe to open port 744?

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 744 is open?

On Linux run "ss -ltnup 'sport = :744'", on macOS "lsof -nP -i :744", and on Windows "netstat -ano | findstr :744" to see the local process. From another machine, "nmap -p 744 <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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