Port 3900
udt-os and udt_os · TCP/UDP
| Range | Registered port (1024–49151) |
|---|---|
| Protocol | TCP/UDP |
| Service | udt-os and udt_os |
Frequently asked questions
What is port 3900 used for?
Port 3900 is registered with the IANA for udt-os and udt_os (TCP/UDP). Description: Unidata UDT OS IANA assigned this well-formed service name as a replacement for "udt_os".; Unidata UDT OS.
Is port 3900 a well-known port?
No. Port 3900 is in the range 1024–49151 (registered or user ports). Ordinary programs may open it without root privileges.
How do I check whether port 3900 is open?
Locally on Linux with ss -tulpn | grep ':3900\b', on Windows with netstat -ano | findstr :3900. To test a remote host use Test-NetConnection <host> -Port 3900 in PowerShell or nc -zv <host> 3900 on Linux/macOS.
How do I open port 3900 in the firewall?
Ubuntu/Debian (ufw): sudo ufw allow 3900/tcp. Fedora/RHEL (firewalld): sudo firewall-cmd --add-port=3900/tcp --permanent, then firewall-cmd --reload. Windows (PowerShell as administrator): New-NetFirewallRule -DisplayName "Port 3900" -Direction Inbound -Protocol TCP -LocalPort 3900 -Action Allow.
IANA registry entries
| Protocol | Service | Description (IANA) |
|---|---|---|
| TCP | udt-os | Unidata UDT OS IANA assigned this well-formed service name as a replacement for "udt_os". |
| TCP | udt_os | Unidata UDT OS |
| UDP | udt-os | Unidata UDT OS IANA assigned this well-formed service name as a replacement for "udt_os". |
| UDP | udt_os | Unidata UDT OS |