[Samba] Samba PDC - XP Client refuses to join!

[James Tandy]

Hi all,

I have been setting up a samba3 domain controller, all seems to work 
fins on the samba side, until i try to join a workstation to the domain.

 From a windows XP client, the following happens...
Enter computer properties, computer name tab... click Change...
Enter "SUSSEXMC.COM" in the domain box, click ok
Now is where things start going wrong..
XP waits for a little while, before responding with:

"A Domain Controller for the domain SUSSEXMC.COM could not be contacted"

Clicking details reveals:

"DNS was succesfully queried for the service location (SRV) resource 
record used to locate a domain controller for the domain: SUSSEXMC.COM
The query was for the SRV record for _ldap._tcp.dc._msdcs.SUSSEXMC.COM
The following domain controllers were identified by the query:
smc1.sussexmc.com
Common causes of this error include:
- Host (A) records that map the name of the domain controller to its IP 
addresses are missing or contain incorrect addresses
- Domain controllers registered in DNS are not connected to the network 
or are not running."

Now ALL using the same XP client...
I can verify that the A records are correct using nslookup (Server ip is 
10.10.1.1, reported by DNS server at 10.10.1.1 (Also the machine gets 
its IP address from DHCP on the same server, and this correctly updates 
the forward and reverse dns zones to reflect this))

I can also verify the DC is running, as if i manually enter "\\smc1" or 
"\\smc1.sussexmc.com" into windows explorer (the first time) i am 
prompted for a username/password (and providing valid credntials allows 
me to logon and see the main shares on the PDC (sysvol, netlogon, 
printers), as well as the users home folder).

What am I missing??
James