CyberHunter
Local dataset, no network
// Other services

Port 22003: Opto Host Port 3

Port 22003 is assigned by IANA to optohost003 (Opto Host Port 3).

22003

How optohost003 works

Other services
client:22003optohost003response client:22003optohost003response

The client sends a request to port 22003 and the optohost003 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 22003 dangerous?

We have no specific security note for port 22003. 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 22003

ServicePortTransportDescriptionReferenceUpdated
optohost003 22003 TCP, UDP Opto Host Port 3 - 2006-09

// source: IANA service name and port number registry

03 Check it

Which program uses port 22003, and is it reachable?

Linux

sudo ss -ltnup 'sport = :22003'      # process listening on 22003
sudo lsof -nP -i :22003

macOS

sudo lsof -nP -i :22003

Windows (PowerShell)

Get-NetTCPConnection -LocalPort 22003 -State Listen | Select LocalAddress, OwningProcess
Get-NetUDPEndpoint -LocalPort 22003
netstat -ano | findstr :22003

From another machine

nmap -p 22003 -sV <host>
sudo nmap -sU -p 22003 <host>
nc -zv <host> 22003

Block it in the firewall

sudo ufw deny 22003/tcp                                         # Linux (ufw)
New-NetFirewallRule -DisplayName "Block 22003" -Direction Inbound -LocalPort 22003 -Protocol TCP -Action Block  # Windows
04 FAQ
What is port 22003 used for?

Port 22003 is assigned by IANA to optohost003 (Opto Host Port 3).

Is port 22003 TCP or UDP?

Port 22003 is registered for TCP and UDP.

Is it safe to open port 22003?

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 22003 is open?

On Linux run "ss -ltnup 'sport = :22003'", on macOS "lsof -nP -i :22003", and on Windows "netstat -ano | findstr :22003" to see the local process. From another machine, "nmap -p 22003 <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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