CyberHunter
Local dataset, no network
// Other services

Port 183: OCBinder

Port 183 is assigned by IANA to ocbinder (OCBinder).

183

How ocbinder works

Other services
client:183ocbinderresponse client:183ocbinderresponse

The client sends a request to port 183 and the ocbinder 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 183 dangerous?

We have no specific security note for port 183. 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 183

ServicePortTransportDescriptionReferenceUpdated
ocbinder 183 TCP, UDP OCBinder - -

// source: IANA service name and port number registry

03 Check it

Which program uses port 183, and is it reachable?

Linux

sudo ss -ltnup 'sport = :183'      # process listening on 183
sudo lsof -nP -i :183

macOS

sudo lsof -nP -i :183

Windows (PowerShell)

Get-NetTCPConnection -LocalPort 183 -State Listen | Select LocalAddress, OwningProcess
Get-NetUDPEndpoint -LocalPort 183
netstat -ano | findstr :183

From another machine

nmap -p 183 -sV <host>
sudo nmap -sU -p 183 <host>
nc -zv <host> 183

Block it in the firewall

sudo ufw deny 183/tcp                                         # Linux (ufw)
New-NetFirewallRule -DisplayName "Block 183" -Direction Inbound -LocalPort 183 -Protocol TCP -Action Block  # Windows
04 FAQ
What is port 183 used for?

Port 183 is assigned by IANA to ocbinder (OCBinder).

Is port 183 TCP or UDP?

Port 183 is registered for TCP and UDP.

Is it safe to open port 183?

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 183 is open?

On Linux run "ss -ltnup 'sport = :183'", on macOS "lsof -nP -i :183", and on Windows "netstat -ano | findstr :183" to see the local process. From another machine, "nmap -p 183 <host>" shows whether it is reachable.

05 Related
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