Cannot find ticket for requested realm while validating credentials
In general, this FAQ deals with the freely available MIT releases of Kerberos.If a question deals specifically with another implementation of Kerberos, then it will be explicitly mentioned.MIT provides Kerberos in source form, so that anyone who wishes to use it may look over the code for themselves and assure themselves that the code is trustworthy.In addition, for those who prefer to rely on a professional supported product, Kerberos is available as a product from many different vendors.
Thus, applications which send an unencrypted password over the network are extremely vulnerable.(After all, firewalls are simply a less extreme example of the dictum that there is nothing more secure then a computer which is not connected to the network --- and powered off!) In many places, these restrictions are simply unrealistic and unacceptable.Most of the really damaging incidents of computer crime are carried out by insiders.Firewalls also have a significant disadvantage in that they restrict how your users can use the Internet.
I have seen references in "The Devil's Dictionary" that claim it is Kerberos, but when I checked this myself I only found the "Cerberus" variant. An excellent overview that covers all of the important details of the Kerberos protocol.