root/boston.example.com@EXAMPLE.COM

A principal that is associated with the root account on an NFS client. This principal is called a root principal and is needed for authenticated NFS-mounting to succeed.

host/boston.example.com@EXAMPLE.COM

A principal that is used by the Kerberized applications (klist and kprop, for example). This principal is called a host or service principal.

username@EXAMPLE.COM

A principal for a user. 

username/admin@EXAMPLE.COM

An admin principal that can be used to administer the KDC database.

nfs/boston.example.com@EXAMPLE.COM

A principal that is used by the NFS service. This principal can be used instead of a host principal.

K/M@EXAMPLE.COM

The master key name principal. There is one master key name principal that is associated with each master KDC. 

kadmin/history@EXAMPLE.COM

A principal which includes a key used to keep password histories for other principals. Each master KDC has one of these principals. 

kadmin/kdc1.example.com@EXAMPLE.COM

A principal for the master KDC server that allows access to the KDC by using kadmind.

changepw/kdc1.example.com@EXAMPLE.COM

A principal for the master KDC server that allows access to the KDC when you are changing passwords. 

krbtgt/EXAMPLE.COM@EXAMPLE.COM

This principal is used when you generate a ticket-granting ticket.