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// Other services

Port 4433: Versile Object Protocol

Port 4433 is assigned by IANA to vop (Versile Object Protocol).

4433

How vop works

Other services
client:4433vopresponse client:4433vopresponse

The client sends a request to port 4433 and the vop service answers.

Transport
TCP
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 4433 dangerous?

We have no specific security note for port 4433. 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 4433

ServicePortTransportDescriptionReferenceUpdated
vop 4433 TCP Versile Object Protocol - 2012-02-01
-4433-Reserved--

// source: IANA service name and port number registry

03 Check it

Which program uses port 4433, and is it reachable?

Linux

sudo ss -ltnup 'sport = :4433'      # process listening on 4433
sudo lsof -nP -i :4433

macOS

sudo lsof -nP -i :4433

Windows (PowerShell)

Get-NetTCPConnection -LocalPort 4433 -State Listen | Select LocalAddress, OwningProcess
Get-NetUDPEndpoint -LocalPort 4433
netstat -ano | findstr :4433

From another machine

nmap -p 4433 -sV <host>
nc -zv <host> 4433

Block it in the firewall

sudo ufw deny 4433/tcp                                         # Linux (ufw)
New-NetFirewallRule -DisplayName "Block 4433" -Direction Inbound -LocalPort 4433 -Protocol TCP -Action Block  # Windows
04 FAQ
What is port 4433 used for?

Port 4433 is assigned by IANA to vop (Versile Object Protocol).

Is port 4433 TCP or UDP?

Port 4433 is registered for TCP.

Is it safe to open port 4433?

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 4433 is open?

On Linux run "ss -ltnup 'sport = :4433'", on macOS "lsof -nP -i :4433", and on Windows "netstat -ano | findstr :4433" to see the local process. From another machine, "nmap -p 4433 <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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