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// Other services

Port 1781: answersoft-lm

Port 1781 is assigned by IANA to answersoft-lm (answersoft-lm).

1781

How answersoft-lm works

Other services
client:1781answersoft-lmresponse client:1781answersoft-lmresponse

The client sends a request to port 1781 and the answersoft-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 1781 dangerous?

We have no specific security note for port 1781. 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 1781

ServicePortTransportDescriptionReferenceUpdated
answersoft-lm 1781 TCP, UDP answersoft-lm - -

// source: IANA service name and port number registry

03 Check it

Which program uses port 1781, and is it reachable?

Linux

sudo ss -ltnup 'sport = :1781'      # process listening on 1781
sudo lsof -nP -i :1781

macOS

sudo lsof -nP -i :1781

Windows (PowerShell)

Get-NetTCPConnection -LocalPort 1781 -State Listen | Select LocalAddress, OwningProcess
Get-NetUDPEndpoint -LocalPort 1781
netstat -ano | findstr :1781

From another machine

nmap -p 1781 -sV <host>
sudo nmap -sU -p 1781 <host>
nc -zv <host> 1781

Block it in the firewall

sudo ufw deny 1781/tcp                                         # Linux (ufw)
New-NetFirewallRule -DisplayName "Block 1781" -Direction Inbound -LocalPort 1781 -Protocol TCP -Action Block  # Windows
04 FAQ
What is port 1781 used for?

Port 1781 is assigned by IANA to answersoft-lm (answersoft-lm).

Is port 1781 TCP or UDP?

Port 1781 is registered for TCP and UDP.

Is it safe to open port 1781?

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 1781 is open?

On Linux run "ss -ltnup 'sport = :1781'", on macOS "lsof -nP -i :1781", and on Windows "netstat -ano | findstr :1781" to see the local process. From another machine, "nmap -p 1781 <host>" shows whether it is reachable.

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