IRC (alternate)
What is Port 6661?
Port 6661 is part of the 6660-6669 range commonly used for IRC (Internet Relay Chat) server connections. IRC servers typically listen on multiple ports in this range to provide connectivity options. The use of multiple ports allows networks to distribute connections and accommodate users on networks with different port restrictions. Like other ports in this range, connections on port 6661 are unencrypted. IRC remains active in developer communities, open-source projects, and security research circles. Modern IRC networks encourage users to connect via TLS-encrypted port 6697 instead of the unencrypted ports in this range.
Common Uses
- IRC server connections
- IRC network alternative connection port
- IRC bouncer connections
- Developer community chat
Technical Details
Copy-paste commands to check port 6661 (IRC (alternate)) from your terminal
Test connectivity
nc -zv example.com 6661
curl -v --max-time 5 http://example.com:6661/
telnet example.com 6661
nmap -p 6661 -sV example.com
(echo > /dev/tcp/example.com/6661) 2>/dev/null && echo "open" || echo "closed"
Open port in firewall
sudo ufw allow 6661/tcp
sudo iptables -A INPUT -p tcp --dport 6661 -j ACCEPT
sudo firewall-cmd --permanent --add-port=6661/tcp && sudo firewall-cmd --reload
Security Considerations
Unencrypted IRC traffic is visible to network observers. Use port 6697 with TLS for encrypted connections. Monitor for unauthorized IRC usage as it can indicate botnet command-and-control activity. Implement SASL authentication.
Popular Ports Reference
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