Port 300
tacacss · TCP/UDP
| Range | System/well-known port (0–1023) |
|---|---|
| Protocol | TCP/UDP |
| Service | tacacss |
| Reference | RFC 9887 |
| Registered | 2025-07-15 |
Frequently asked questions
What is port 300 used for?
Port 300 is registered with the IANA for tacacss (TCP/UDP). Description: TLS Secure Login Host Protocol (TACACSS); Reserved.
Is port 300 a well-known port?
Yes. Port 300 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 300 is open?
Locally on Linux with ss -tulpn | grep ':300\b', on Windows with netstat -ano | findstr :300. To test a remote host use Test-NetConnection <host> -Port 300 in PowerShell or nc -zv <host> 300 on Linux/macOS.
How do I open port 300 in the firewall?
Ubuntu/Debian (ufw): sudo ufw allow 300/tcp. Fedora/RHEL (firewalld): sudo firewall-cmd --add-port=300/tcp --permanent, then firewall-cmd --reload. Windows (PowerShell as administrator): New-NetFirewallRule -DisplayName "Port 300" -Direction Inbound -Protocol TCP -LocalPort 300 -Action Allow.
IANA registry entries
| Protocol | Service | Description (IANA) |
|---|---|---|
| TCP | tacacss | TLS Secure Login Host Protocol (TACACSS) |
| UDP | – | Reserved |