Port 4391
apwi-imserver · TCP/UDP
| Range | Registered port (1024–49151) |
|---|---|
| Protocol | TCP/UDP |
| Service | apwi-imserver |
| Registered | 2009-02-12 |
Frequently asked questions
What is port 4391 used for?
Port 4391 is registered with the IANA for apwi-imserver (TCP/UDP). Description: American Printware IMServer Protocol; Reserved.
Is port 4391 a well-known port?
No. Port 4391 is in the range 1024–49151 (registered or user ports). Ordinary programs may open it without root privileges.
How do I check whether port 4391 is open?
Locally on Linux with ss -tulpn | grep ':4391\b', on Windows with netstat -ano | findstr :4391. To test a remote host use Test-NetConnection <host> -Port 4391 in PowerShell or nc -zv <host> 4391 on Linux/macOS.
How do I open port 4391 in the firewall?
Ubuntu/Debian (ufw): sudo ufw allow 4391/tcp. Fedora/RHEL (firewalld): sudo firewall-cmd --add-port=4391/tcp --permanent, then firewall-cmd --reload. Windows (PowerShell as administrator): New-NetFirewallRule -DisplayName "Port 4391" -Direction Inbound -Protocol TCP -LocalPort 4391 -Action Allow.
IANA registry entries
| Protocol | Service | Description (IANA) |
|---|---|---|
| TCP | apwi-imserver | American Printware IMServer Protocol |
| UDP | – | Reserved |