CyberHunter
Local dataset, no network
// Other services

Port 4042: LDXP

Port 4042 is assigned by IANA to ldxp (LDXP).

4042

How ldxp works

Other services
client:4042ldxpresponse client:4042ldxpresponse

The client sends a request to port 4042 and the ldxp 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)
01 Security

Is port 4042 dangerous?

We have no specific security note for port 4042. 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 4042

ServicePortTransportDescriptionReferenceUpdated
ldxp 4042 TCP, UDP LDXP - -

// source: IANA service name and port number registry

03 Check it

Which program uses port 4042, and is it reachable?

Linux

sudo ss -ltnup 'sport = :4042'      # process listening on 4042
sudo lsof -nP -i :4042

macOS

sudo lsof -nP -i :4042

Windows (PowerShell)

Get-NetTCPConnection -LocalPort 4042 -State Listen | Select LocalAddress, OwningProcess
Get-NetUDPEndpoint -LocalPort 4042
netstat -ano | findstr :4042

From another machine

nmap -p 4042 -sV <host>
sudo nmap -sU -p 4042 <host>
nc -zv <host> 4042

Block it in the firewall

sudo ufw deny 4042/tcp                                         # Linux (ufw)
New-NetFirewallRule -DisplayName "Block 4042" -Direction Inbound -LocalPort 4042 -Protocol TCP -Action Block  # Windows
04 FAQ
What is port 4042 used for?

Port 4042 is assigned by IANA to ldxp (LDXP).

Is port 4042 TCP or UDP?

Port 4042 is registered for TCP and UDP.

Is it safe to open port 4042?

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 4042 is open?

On Linux run "ss -ltnup 'sport = :4042'", on macOS "lsof -nP -i :4042", and on Windows "netstat -ano | findstr :4042" to see the local process. From another machine, "nmap -p 4042 <host>" shows whether it is reachable.

05 Related

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