So I have Samba 3.5 set up to use pam to authenticate against kerberos. This seems to be working fine when I connect to the from a linux system using smbclient. However, when I try to connect from a windows system, it fails. I cranked up the debug level, but I'm unable to figure why this does not work. I feel I'm missing a component to this. I use samba on a handful of our servers, but I have them authenticate back to the windows domain. This system is different and I'm just missing something here. It's a basic set up right now. smb.conf [global] workgroup = MYGROUP server string = Samba Server Version %v log file = /var/log/samba/log.%m max log size = 50 security = user passdb backend = tdbsam encrypt passwords = no client plaintext auth = yes client lanman auth = yes load printers = yes cups options = raw [homes] comment = Home Directories browseable = no writable = yes ; valid users = %S ; valid users = MYDOMAIN\%S [printers] comment = All Printers path = /var/spool/samba browseable = no guest ok = no writable = no printable = yes /etc/pam.d/samba auth required pam_env.so auth sufficient pam_unix.so nullok try_first_pass auth requisite pam_succeed_if.so uid >= 500 quiet auth sufficient pam_krb5.so use_first_pass auth required pam_deny.so account required pam_unix.so broken_shadow account sufficient pam_localuser.so account sufficient pam_succeed_if.so uid < 500 quiet account [default=bad success=ok user_unknown=ignore] pam_krb5.so account required pam_permit.so password requisite pam_cracklib.so try_first_pass retry=3 typepassword sufficient pam_unix.so sha512 shadow nis nullok try_first_pass use_authtok password sufficient pam_krb5.so use_authtok password required pam_deny.so session optional pam_keyinit.so revoke session required pam_limits.so session [success=1 default=ignore] pam_succeed_if.so service in crond quiet use_uid session required pam_unix.so session optional pam_krb5.so The system works fine connecting from linux with smbclient, from windows I get "The account is not authorized to log in from this station". I'm guessing this is something simple. thanks!