- 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.
Port 16003: Automation and Control by REGULACE.ORG
Port 16003 is assigned by IANA to alfin (Automation and Control by REGULACE.ORG).
16003
How alfin works
Other servicesThe client sends a request to port 16003 and the alfin service answers.
- Transport
- 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
Is port 16003 dangerous?
We have no specific security note for port 16003. Its risk depends on the program actually listening on it. General advice for other services services:
IANA registry entries for port 16003
| Service | Port | Transport | Description | Reference | Updated |
|---|---|---|---|---|---|
| alfin | 16003 | UDP | Automation and Control by REGULACE.ORG | - | 2010-10-06 |
| - | 16003 | - | Reserved | - | - |
// source: IANA service name and port number registry
Which program uses port 16003, and is it reachable?
Linux
sudo ss -ltnup 'sport = :16003' # process listening on 16003
sudo lsof -nP -i :16003macOS
sudo lsof -nP -i :16003
Windows (PowerShell)
Get-NetTCPConnection -LocalPort 16003 -State Listen | Select LocalAddress, OwningProcess Get-NetUDPEndpoint -LocalPort 16003 netstat -ano | findstr :16003
From another machine
nmap -p 16003 -sV <host> sudo nmap -sU -p 16003 <host> nc -zv <host> 16003
Block it in the firewall
sudo ufw deny 16003/udp # Linux (ufw) New-NetFirewallRule -DisplayName "Block 16003" -Direction Inbound -LocalPort 16003 -Protocol UDP -Action Block # Windows
What is port 16003 used for?
Port 16003 is assigned by IANA to alfin (Automation and Control by REGULACE.ORG).
Is port 16003 TCP or UDP?
Port 16003 is registered for UDP.
Is it safe to open port 16003?
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 16003 is open?
On Linux run "ss -ltnup 'sport = :16003'", on macOS "lsof -nP -i :16003", and on Windows "netstat -ano | findstr :16003" to see the local process. From another machine, "nmap -p 16003 <host>" shows whether it is reachable.
Other other services ports
: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