Although your Kerberos realm can be any ASCII string, convention is to
make it the same as your domain name, in upper-case letters. For
example, hosts in the domain example.com would be in the
Kerberos realm EXAMPLE.COM.
If you need multiple Kerberos realms, MIT recommends that
you use descriptive names which end with your domain name, such as
BOSTON.EXAMPLE.COM and HOUSTON.EXAMPLE.COM.