CyberHunter
Local dataset, no network
// Other services

Port 536: opalis-rdv

Port 536 is assigned by IANA to opalis-rdv (opalis-rdv).

536

How opalis-rdv works

Other services
client:536opalis-rdvresponse client:536opalis-rdvresponse

The client sends a request to port 536 and the opalis-rdv 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 536 dangerous?

We have no specific security note for port 536. 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 536

ServicePortTransportDescriptionReferenceUpdated
opalis-rdv 536 TCP, UDP opalis-rdv - -

// source: IANA service name and port number registry

03 Check it

Which program uses port 536, and is it reachable?

Linux

sudo ss -ltnup 'sport = :536'      # process listening on 536
sudo lsof -nP -i :536

macOS

sudo lsof -nP -i :536

Windows (PowerShell)

Get-NetTCPConnection -LocalPort 536 -State Listen | Select LocalAddress, OwningProcess
Get-NetUDPEndpoint -LocalPort 536
netstat -ano | findstr :536

From another machine

nmap -p 536 -sV <host>
sudo nmap -sU -p 536 <host>
nc -zv <host> 536

Block it in the firewall

sudo ufw deny 536/tcp                                         # Linux (ufw)
New-NetFirewallRule -DisplayName "Block 536" -Direction Inbound -LocalPort 536 -Protocol TCP -Action Block  # Windows
04 FAQ
What is port 536 used for?

Port 536 is assigned by IANA to opalis-rdv (opalis-rdv).

Is port 536 TCP or UDP?

Port 536 is registered for TCP and UDP.

Is it safe to open port 536?

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 536 is open?

On Linux run "ss -ltnup 'sport = :536'", on macOS "lsof -nP -i :536", and on Windows "netstat -ano | findstr :536" to see the local process. From another machine, "nmap -p 536 <host>" shows whether it is reachable.

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