hi

I have registered my domain somename.ca with another provider.
Now i am trying to have only my vpn.somename.ca redirect to my location
what is needed on the dynu controle panel to redirect ?
- I have create a cname on my registrar to ns2.dynu.com
- I use ddclient that is working and updating correctly

The best way is to change the name servers for your domain name somename.ca at your registrar to Dynu name servers and set up DNS records with Dynu. You can set up the main domain name somename.ca to point to your static server IP and set up a subdomain vpn.somename.ca to point to your dynamic IP address. You can use ddclient to update vpn.somedomain.ca.

If you are not able to use Dynu name servers for your primary domain name, You can sign up for a free third level domain name say testvpn.ddnsfree.com at https://www.dynu.com/en-US/ControlPanel/AddDDNS by using option 1. Then at your current registrar, you can add a CNAME record for vpn.somedomain.ca to point to testvpn.ddnsfree.com. Then you run ddclient to update testvpn.ddnsfree.com. Since you have a CNAME record for vpn.somedomain.ca to point to testvpn.ddnsfree.com, vpn.somedomain.ca will map to the dynamic IP address as well.

Either way, you should remove the CNAME record you added that points somename.ca to ns2.dynu.com.