Just to be pedantic, you only need a registrar to globally register the domain name and associate it with DNS records. You could choose to point your system at

Just to be pedantic, you only need a registrar to globally register the domain name and associate it with DNS records. You could choose to point your system at a locally-controlled DNS server, or edit the local /etc/hosts file, to use user-friendly names without depending on registering the domain with any authority.