From where can I check which is the current registrar of a domain name?
If you want to know the current registrar of specific domain name, you can use the following online tool which will list all of the information from the WHOS database for your domain name:
After the websites has loaded on your screen just enter the desired domain name in the field and click on the search button.
A new page will be displayed containing a list with all plenty of information regarding the domain name.
The line that you have to take a look at is Registrar:
There you can find additional information for the registrar, such as website and contact information.