How to create own domain extension? [closed]

Like bit.ly, goo.gl, is.gd, j.mp, migre.me etc. use their own domain extension .ly, .gl, .gd, .mp, .me etc. How can I create my own personalize domain extension like .gbsif? Please help.

You can't. Only IANA can.

Management of most top-level domains is delegated to responsible organizations by the Internet Corporation for Assigned Names and Numbers (ICANN), which operates the Internet Assigned Numbers Authority (IANA) and is in charge of maintaining the DNS root zone.

• http://en.wikipedia.org/wiki/Top-level_domain

Here's a list of available TLDs:

• http://www.iana.org/domains/root/db/
• http://data.iana.org/TLD/tlds-alpha-by-domain.txt

You can run your own nameserver and add a new tld there. But this won't help you much, as the TLD will only be visible to the users who are using your own nameserver. The "official" TLD like ".ly" are countries, see: official list

The ICANN website does have a Contact page, and one subject category is "New gTLDs", so they probably get requests like this a lot. I don't know if they'd actually create an extension just for you, but if they get a lot of the same requests, I'm sure they'd do something about it.