Principal for service

[Brian Lavender]

Do I have to create a principal for a service? I created a host
principal and then a service principal, and then I added them to my
keytab, but I am not sure if I had to add the service principal. This
is for current Kerberos 5 from MIT.

This is what I did.

addprinc host/foo.example.com at EXAMPLE.COM
addprinc ftp/foo.example.com at EXAMPLE.COM
ktadd host/foo.example.com at EXAMPLE.COM 
ktadd ftp/foo.example.com at EXAMPLE.COM

Is it necessary to add the service?

brian