Port 172
cl-1 and cl/1 · TCP/UDP
| Range | System/well-known port (0–1023) |
|---|---|
| Protocol | TCP/UDP |
| Service | cl-1 and cl/1 |
Frequently asked questions
What is port 172 used for?
Port 172 is registered with the IANA for cl-1 and cl/1 (TCP/UDP). Description: Network Innovations CL/1 IANA assigned this well-formed service name as a replacement for "cl/1".; Network Innovations CL/1.
Is port 172 a well-known port?
Yes. Port 172 is in the range 0–1023 (system or well-known ports). On Linux and macOS only privileged processes may bind to these ports.
How do I check whether port 172 is open?
Locally on Linux with ss -tulpn | grep ':172\b', on Windows with netstat -ano | findstr :172. To test a remote host use Test-NetConnection <host> -Port 172 in PowerShell or nc -zv <host> 172 on Linux/macOS.
How do I open port 172 in the firewall?
Ubuntu/Debian (ufw): sudo ufw allow 172/tcp. Fedora/RHEL (firewalld): sudo firewall-cmd --add-port=172/tcp --permanent, then firewall-cmd --reload. Windows (PowerShell as administrator): New-NetFirewallRule -DisplayName "Port 172" -Direction Inbound -Protocol TCP -LocalPort 172 -Action Allow.
IANA registry entries
| Protocol | Service | Description (IANA) |
|---|---|---|
| TCP | cl-1 | Network Innovations CL/1 IANA assigned this well-formed service name as a replacement for "cl/1". |
| TCP | cl/1 | Network Innovations CL/1 |
| UDP | cl-1 | Network Innovations CL/1 IANA assigned this well-formed service name as a replacement for "cl/1". |
| UDP | cl/1 | Network Innovations CL/1 |