The scenario is you have domains with a registrar. Typical good practice is that the login to the registrar is an external email address. This way if any issues with the registar, you are not locked out.

If you do not have Gmail, Yahoo, Hotmail, any other 3P provider, how do you manage this scenario? The goal is to not have any 3P mail and be self-contained within your own domain and email management.

Edit This scenario is for a home user that has domains for various projects, purposes however currently uses a separate hotmail, gmail, etc for the login to the registrar.