Port 84
ctf · TCP/UDP
| Range | System/well-known port (0–1023) |
|---|---|
| Protocol | TCP/UDP |
| Service | ctf |
Frequently asked questions
What is port 84 used for?
Port 84 is registered with the IANA for ctf (TCP/UDP). Description: Common Trace Facility.
Is port 84 a well-known port?
Yes. Port 84 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 84 is open?
Locally on Linux with ss -tulpn | grep ':84\b', on Windows with netstat -ano | findstr :84. To test a remote host use Test-NetConnection <host> -Port 84 in PowerShell or nc -zv <host> 84 on Linux/macOS.
How do I open port 84 in the firewall?
Ubuntu/Debian (ufw): sudo ufw allow 84/tcp. Fedora/RHEL (firewalld): sudo firewall-cmd --add-port=84/tcp --permanent, then firewall-cmd --reload. Windows (PowerShell as administrator): New-NetFirewallRule -DisplayName "Port 84" -Direction Inbound -Protocol TCP -LocalPort 84 -Action Allow.
IANA registry entries
| Protocol | Service | Description (IANA) |
|---|---|---|
| TCP | ctf | Common Trace Facility |
| UDP | ctf | Common Trace Facility |