CyberHunter
Local dataset, no network
// Other services

Port 506: ohimsrv

Port 506 is assigned by IANA to ohimsrv (ohimsrv).

506

How ohimsrv works

Other services
client:506ohimsrvresponse client:506ohimsrvresponse

The client sends a request to port 506 and the ohimsrv 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 506 dangerous?

We have no specific security note for port 506. 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 506

ServicePortTransportDescriptionReferenceUpdated
ohimsrv 506 TCP, UDP ohimsrv - -

// source: IANA service name and port number registry

03 Check it

Which program uses port 506, and is it reachable?

Linux

sudo ss -ltnup 'sport = :506'      # process listening on 506
sudo lsof -nP -i :506

macOS

sudo lsof -nP -i :506

Windows (PowerShell)

Get-NetTCPConnection -LocalPort 506 -State Listen | Select LocalAddress, OwningProcess
Get-NetUDPEndpoint -LocalPort 506
netstat -ano | findstr :506

From another machine

nmap -p 506 -sV <host>
sudo nmap -sU -p 506 <host>
nc -zv <host> 506

Block it in the firewall

sudo ufw deny 506/tcp                                         # Linux (ufw)
New-NetFirewallRule -DisplayName "Block 506" -Direction Inbound -LocalPort 506 -Protocol TCP -Action Block  # Windows
04 FAQ
What is port 506 used for?

Port 506 is assigned by IANA to ohimsrv (ohimsrv).

Is port 506 TCP or UDP?

Port 506 is registered for TCP and UDP.

Is it safe to open port 506?

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 506 is open?

On Linux run "ss -ltnup 'sport = :506'", on macOS "lsof -nP -i :506", and on Windows "netstat -ano | findstr :506" to see the local process. From another machine, "nmap -p 506 <host>" shows whether it is reachable.

05 Related
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