CyberHunter
Local dataset, no network
// Other services

Port 4839: Varadero-2

Port 4839 is assigned by IANA to varadero-2 (Varadero-2).

4839

How varadero-2 works

Other services
client:4839varadero-2response client:4839varadero-2response

The client sends a request to port 4839 and the varadero-2 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 4839 dangerous?

We have no specific security note for port 4839. 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 4839

ServicePortTransportDescriptionReferenceUpdated
varadero-2 4839 TCP, UDP Varadero-2 - -

// source: IANA service name and port number registry

03 Check it

Which program uses port 4839, and is it reachable?

Linux

sudo ss -ltnup 'sport = :4839'      # process listening on 4839
sudo lsof -nP -i :4839

macOS

sudo lsof -nP -i :4839

Windows (PowerShell)

Get-NetTCPConnection -LocalPort 4839 -State Listen | Select LocalAddress, OwningProcess
Get-NetUDPEndpoint -LocalPort 4839
netstat -ano | findstr :4839

From another machine

nmap -p 4839 -sV <host>
sudo nmap -sU -p 4839 <host>
nc -zv <host> 4839

Block it in the firewall

sudo ufw deny 4839/tcp                                         # Linux (ufw)
New-NetFirewallRule -DisplayName "Block 4839" -Direction Inbound -LocalPort 4839 -Protocol TCP -Action Block  # Windows
04 FAQ
What is port 4839 used for?

Port 4839 is assigned by IANA to varadero-2 (Varadero-2).

Is port 4839 TCP or UDP?

Port 4839 is registered for TCP and UDP.

Is it safe to open port 4839?

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 4839 is open?

On Linux run "ss -ltnup 'sport = :4839'", on macOS "lsof -nP -i :4839", and on Windows "netstat -ano | findstr :4839" to see the local process. From another machine, "nmap -p 4839 <host>" shows whether it is reachable.

05 Related
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