6697
Encrypted IRC connections over SSL/TLS
IRC over SSL/TLS
What is port 6697?
Port 6697 is used for SSL/TLS-encrypted IRC connections. It is strongly recommended over the unencrypted port 6667 to protect chat sessions and credentials. Most modern IRC networks including Libera.Chat and OFTC support TLS on port 6697.
Quick checks
$
nc -zv example.com 6697
$
nmap -p 6697 example.com
$
telnet example.com 6697