samba - Apr 2007 - Issue joining a PC to a Samba domain from a subnet other the one that Samba PDC resides on

Hello,

Thanks in advance for taking the time to look at this issue. We are
currently experiencing an issue with PC's not being able to join a Samba PDC
controlled domain when the PC's are located outside of the subnet that the
Samba PDC is part of. The PC's are located in the same physical building as
the PDC, connecting over a Cisco VLAN to the Samba PDC subnet. For example,
the PDC is part of the 192.168.1.x subnet and the client PC is part of
192.168.70.x . subnet.  If the client tries to join the domain from this
network segment, then error message;

Logon failure: unknown username or bad password

will appear on the client end. The client PC's are Windows XP SP2 systems.
They have File & Printer sharing enabled, disabled Windows Firewall,
disabled 3 digital signing policies. These same PC settings will work in
respect to joining the domain when I am wired into the same network segment
as the PDC. However, once the same PC is moved out of the server subnet,
then the domain join will fail. I have read a posting on this on the Samba
list which recommends removing the loopback address as a resolution. Can
anyone please explain why this would resolve this problem?

We are currently running the following setup on the PDC;

OS                =    Suse Linux Server version 9.1
Server            =    Samba 3.0.20b-3.4
Linux Kernel   =    Linux version 2.6.5-7.97-smp

I have tried to add an lmhosts entry(ie.129.x.x.x Cancer #PRE #DOM:cruk) to
the PC's that are not on the same subnet as the PDC, and the problem still
appears to occur.

If anyone could please provide some insight to the cause of this problem and
how it can be resolve, I would appreciate it.

Thanks,

Mark