When using the IPv6 address with your domain, you may wish to verify if an HTTP connection on IPv6 is used.
1. Locate the IPv6 address for your domain. Go to this location in WHM.
WHM: Home »IP Functions »Assign IPv6 Address --> Select an Account
Find your account, and ensure it is marked 'Enabled'
2. Select it, and on the right-hand side will display your IPv6 address.
3. Copy/Paste that IPv6 to use in step 5.
4. Log into a remote Unix-based server via SSH.
5. Use the command 'curl' with the following options to see the output.
IPv6 address: 2607:f8b0:3000:801::230e
Network Interface of remote server: eth0
Command to use:
curl -g -d -k -v --interface eth0 [2607:f8b0:3000:801::230e] https://domain.tld/
6. Observe output, look for the connection to port 443, and response:
* About to connect() to domain.tld port 443 (#1)
* Trying 2607:f8b0:3000:801::230e...
* Local Interface eth0 is ip 2620:0:28a4:a079:f816:3eff:fe95:7d6e using address family 10
* Local port: 0
* Connected to domain.tld (2607:f8b0:3000:801::230e) port 443 (#1)
This shows the HTTPS connection reached the server, IPv6 with port 443, and asked for the domain name.