[Samba] join linux client on samba 3 domain

[Pascal Legrand]

Hello,
i've got a problem with a linux client joined to a samba3 domain. I join
it with this command "net rpc join -S 192.168.151.237 -U admin" after
configuring winbind in smb.conf.

I follow this french tuto :
http://doc.ubuntu-fr.org/tutoriel/comment_integrer_machine_ubuntu_domaine_nt_samba

It works fine, but after a few days, it's impossible to login.

It seems that the machine account expired.

I have to use again the "net rpc join" command to make it works.

I have this problem only with linux clients, all my windows clients
works fine.

How i could find what is the problem ?

Thanks for your help

Pascal