Port 6667: IRC (de facto)
Port 6667 is the de facto standard port for IRC, Internet Relay Chat, even though 194 is the officially registered one. Most public IRC networks also offer an encrypted option on port 6697.
| Port number | 6667 |
|---|---|
| Service | Internet Relay Chat |
| Protocol | TCP |
| Category | Chat & messaging |
| Default encryption | No |
How do I check whether port 6667 is open?
Port 6667 carries TCP, so a connection either completes its handshake or it does not, which makes the check definitive.
| Question | Command | What to know |
|---|---|---|
| Is it open on a remote host? | nc -vz example.com 6667 | A TCP handshake either completes or it does not, so netcat gives a definitive answer in one line. |
| Same check on Windows | Test-NetConnection example.com -Port 6667 | Built into PowerShell. TcpTestSucceeded in the output is the answer; telnet is not installed by default on modern Windows. |
| What is listening locally? | ss -tlnp | grep ':6667 ' | Lists the process bound to port 6667 on Linux. On macOS use lsof -nP -iTCP:6667 -sTCP:LISTEN, on Windows netstat -ano | findstr :6667 |
Replace example.com with the host you are testing. A blocked port and a port with nothing listening on it look identical from the outside, so if a service should be running, check locally before blaming the firewall.
Frequently asked questions
What is port 6667 used for?
Port 6667 is the de facto standard port for IRC, Internet Relay Chat, even though 194 is the officially registered one. Most public IRC networks also offer an encrypted option on port 6697.
Is port 6667 TCP or UDP?
Port 6667 (IRC (de facto)) uses TCP.
Is port 6667 secure?
Port 6667 is not encrypted by default. Where possible, use an encrypted alternative or tunnel it over TLS or a VPN.
Should I open port 6667 on my firewall?
Only if you specifically need IRC (de facto). Expose it to the smallest set of trusted sources, and never open database or Windows-service ports to the whole internet.