Port 4321
rwhois · TCP/UDP
| Range | Registered port (1024–49151) |
|---|---|
| Protocol | TCP/UDP |
| Service | rwhois |
| Reference | RFC 2167 |
Frequently asked questions
What is port 4321 used for?
Port 4321 is registered with the IANA for rwhois (TCP/UDP). Description: Remote Who Is.
Is port 4321 a well-known port?
No. Port 4321 is in the range 1024–49151 (registered or user ports). Ordinary programs may open it without root privileges.
How do I check whether port 4321 is open?
Locally on Linux with ss -tulpn | grep ':4321\b', on Windows with netstat -ano | findstr :4321. To test a remote host use Test-NetConnection <host> -Port 4321 in PowerShell or nc -zv <host> 4321 on Linux/macOS.
How do I open port 4321 in the firewall?
Ubuntu/Debian (ufw): sudo ufw allow 4321/tcp. Fedora/RHEL (firewalld): sudo firewall-cmd --add-port=4321/tcp --permanent, then firewall-cmd --reload. Windows (PowerShell as administrator): New-NetFirewallRule -DisplayName "Port 4321" -Direction Inbound -Protocol TCP -LocalPort 4321 -Action Allow.
IANA registry entries
| Protocol | Service | Description (IANA) |
|---|---|---|
| TCP | rwhois | Remote Who Is |
| UDP | rwhois | Remote Who Is |