AD keytabs for unix host

[melissa_benkyo]

hello all,

I'm quite confused about this situation. I have read the step by step
kerberos interoperability and it is stated that I should add the unix
host and ktutil the keytab file created.

I'm trying to login from unix machine using AD users. If I removed the
keytab file , it still works. I'm not sure then what the keytab is
for. is this a bug on my kerberos? even kinit works without the keytab
file???

thanks! any help is much appreciated!