kerberos V with SSH : password reasked

[nat]

I'm installing kerberos on a debian distrib (current sarge), the
installation looks good, ticket are correctly created when a user ask
for a connection :

Ticket cache: FILE:/tmp/[...]
Default principal: [...]@[DOMAIN]

Valid starting     Expires            Service principal
02/02/05 22:12:46  02/03/05 08:12:45  krbtgt/[DOMAIN]@[DOMAIN]

Kerberos 4 ticket cache: /tmp/[...]
klist: You have no tickets cached


But after if he does a ssh on the machine, the kerberos password is
aked...

I don't know what I sould do to correct this problem. Can so help me ?
I'm a totaly lost in krb5.

thks
nat