samba - Mar 2011 - can connect to 2 samba servers by name but to one by IP only

(This is a follow up on an earlier post but I have tried to summarize a 
little better.)

I am having problems connecting to one samba server by host name (e.g  
"net use \\servername" or via windows explorer) over IPSec VPN. I can 
connect via "net use \\IPADDRESS." For every other Samba or Windows 
server I can connect via host name.  The problem host is the Samba PDC 
running Samba 3.4.7 on Solaris 10.



I use sonicwall VPN client which has a "virtual" nic, which gets an IP
address (including DNS and  wins server info) from the company DHCP 
server, and on the same subnet as the servers and other machines on the 
network.   All servers are listed in DNS-  I can resolve them with ping 
and nslookup.



If I update lmhosts on my PC, I can use "net use \\pdc1." This
suggests
that XP is NOT using DNS to resolve host name for this host. But that 
doesn't make sense, since every other host can be accessed by name.


"nbtstat -r" ("Lists names resolved by broadcast and via
WINS") only
shows the other xp machine on my home network, not any of the machines 
on the company network, so I am pretty sure I am not resolving server 
names via broadcast or wins. Updating hosts file on my XP machine 
doesn't help either.    WINS does not seem to work over the VPN if if a 
WINS server IP address to assigned to the client (I submitted a 
separated post on this.)


It also should not matter how the server resolves hostnames.    However, 
that is the only variable I can think of at this point.  Maybe for most 
client-to-server name lookups DNS works fine (and therefore works 
whether the client is on the LAN or connecting via VPN.)   However, 
maybe for this one server only WINS or LMHOSTS works, and since WINS 
traffic seems to be blocked by the VPN I am left with LMHOSTS as the 
only option.


I ran snoop on my samba servers to capture Ethernet packets between the 
remote XP machine and the samba servers. It does show that the


With a successful connection:

The client sends what appears to be an empty SMB packet to the server on
port 445

SMB: ----- SMB: -----
SMB:
SMB: ""
SMB:



The server responds with a similar packet, then the client starts sending
more information to the server e.g.

NBT: ----- NBT Header -----
NBT:
NBT: Type = SESSION MESSAGE
NBT: Length = 133 bytes
NBT:
SMB: ----- SMB Header -----
SMB:
SMB: CLIENT REQUEST
SMB: Command code = 0x72
SMB: Command name = SMBnegprot
SMB:
SMB: SMB Status:
SMB: - Error class = No error
SMB: - Error code = No error
SMB:
SMB: Header:
SMB: - Tree ID (TID) = 0x0000
SMB: - Process ID (PID) = 0xfeff
SMB: - User ID (UID) = 0x0000
SMB: - Multiplex ID (MID) = 0x0000
SMB: - Flags summary = 0x18
SMB: - Flags2 summary = 0xc853
SMB:
SMB: ByteCount = 98
SMB: Dialect String = PC NETWORK PROGRAM 1.0
SMB: Dialect String = LANMAN1.0
SMB: Dialect String = Windows for Workgroups 3.1a
SMB: Dialect String = LM1.2X002
SMB: Dialect String = LANMAN2.1
SMB: Dialect String = NT LM 0.12
SMB:





However which a failed connection, it looks like the client sends the empty
SMB packet, the server does respond with an empty SMB packet, but then the
client just sends another empty SMB packet.

I am stumped.

I appreciate any advice.