You can use websites like DomainTools or the WHOIS Lookup provided by ICANN look-up up information about your domain. Information like the Registrar and Name Server can be indicators of your domain’s provider.
More technologically savvy users can use their computer's Terminal program to look up the domain’s name server by typing in dig -t NS [your domain]. For example, ‘dig -t NS bitly.is’. A domain’s name server can be a good indicator of the domain provider but is depended on the provider’s naming methods.
Keep these things in mind as you choose and set up a custom domain:
- The domain for your short links must be different than your website domain.
- It can't be more than 32 characters long, including the dot.
- If you haven't added one yet, Bitly offers a complimentary domain. However, if you add your own domain, you won't be able to redeem this offer later.