TCPRegistered PortFirewall: Usually Closed
6663

IRC (alternate)

What is Port 6663?

Port 6663 is part of the standard IRC port range 6660-6669 used by IRC servers for client connections. IRC networks configure their servers to accept connections on multiple ports to provide redundancy and accommodate different network environments. Some corporate and educational firewalls may block specific ports, so having multiple options helps IRC users connect. The port provides the same unencrypted IRC functionality as other ports in the range. IRC continues to serve as real-time communication infrastructure for technical projects and communities that value open protocols and decentralization.

Common Uses

  • IRC server connections
  • Alternative IRC connection endpoint
  • IRC client fallback connection
  • Technical community communication

Technical Details

Port Number6663
ProtocolTCP
CategoryRegistered
Service NameIRC (alternate)
Default FirewallUsually Closed
Port Test Commands

Copy-paste commands to check port 6663 (IRC (alternate)) from your terminal

Test connectivity

Netcat (nc)Check if TCP port is reachable
nc -zv example.com 6663
curl (HTTP)Test HTTP response on this port
curl -v --max-time 5 http://example.com:6663/
TelnetBasic TCP port connectivity check
telnet example.com 6663
nmapScan port 6663 with service detection
nmap -p 6663 -sV example.com
Bash /dev/tcpPure bash TCP check (no extra tools needed)
(echo > /dev/tcp/example.com/6663) 2>/dev/null && echo "open" || echo "closed"

Open port in firewall

UFW (Ubuntu / Debian)
sudo ufw allow 6663/tcp
iptables
sudo iptables -A INPUT -p tcp --dport 6663 -j ACCEPT
firewalld (RHEL / CentOS)
sudo firewall-cmd --permanent --add-port=6663/tcp && sudo firewall-cmd --reload

Security Considerations

!

Unencrypted. Use TLS-enabled port 6697. Monitor for unauthorized IRC traffic which may indicate compromise.

Popular Ports Reference

The most commonly used and referenced network ports

Related Ports