I installed a DNS server on my VPS running Windows 2012 server. I created ns1.mydomain.com and ns2.mydomain.com pointing to the vps ip address. Now do I have to change something on the domain registrar ?
Yes, you need to contact the registrar and tell them to list
That said, I would advise against having all of your nameservers pointing to the same VPS. If anything happens to that VPS, your entire domain will go down. You should at the very least get a second VPS hosted in a different datacenter for