[Samba] 4.2.14 (or newer) support "Windows for Workgroups 3.1a"?

[Andrea Baldoni]

Hello.

I need to let Windows for Workgroup 3.11 clients (industrial machinery)
connect to shares in the PDC samba Version 4.2.14-Debian.

I started to be able to connect to shares exported by domain members windows
professional (7, 10) machines (share permissions include "domain users"), after
I added "lanman auth = yes" to PDC and updated the user password,
though it's not stable (sometimes the client stop to access/list files in the
share; rebooting the exporting windows machine sometimes cures the problem,
sometimes I need to restart samba process in the PDC), but I never connect to
shares exported by the PDC itself. Of course every other windows client connect
to the PDC shares without problems or instability. The instability of the old
WfW 3.11 clients existed even before I replaced the former windows 2008 PDC
with samba, but it (seems it) was less severe and anyway always cured by
rebooting the exporting windows pro machine, the PDC never needed a reboot
(perhaps it would have cured the problem, but it was simpler to reboot the
exporting windows pro machine, so no one tried to reboot the server).
I don't know if Windows for Workgroup machines were able to connect to the
shares exported from the former windows 2008 PDC.

I traced client traffic, it seems that the samba PDC doesn't answer at all to
the SMBnegprot (REQUEST) (other than TCP handshake). I don't see the expected
SMBnegprot (REPLY).

>>> NBT Session Packet
NBT Session Message
Flags=0x0
Length=142 (0x8e)

SMB PACKET: SMBnegprot (REQUEST)
SMB Command   =  0x72
Error class   =  0x0
Error code    =  0 (0x0)
Flags1        =  0x0
Flags2        =  0x0
Tree ID       =  0 (0x0)
Proc ID       =  32018 (0x7d12)
UID           =  0 (0x0)
MID           =  1025 (0x401)
Word Count    =  0 (0x0)
smb_bcc=107
Dialect=PC NETWORK PROGRAM 1.0
Dialect=MICROSOFT NETWORKS 3.0
Dialect=DOS LM1.2X002
Dialect=DOS LANMAN2.1
Dialect=Windows for Workgroups 3.1a

I added various config lines related to protocol and auth without any
success.

testparm -v | grep protocol

server max protocol = SMB3
server min protocol = LANMAN1
client max protocol = default
client min protocol = CORE
client ipc max protocol = default
client ipc min protocol = default

testparm -v | grep auth

auth methods = 
lanman auth = Yes
ntlm auth = Yes
raw NTLMv2 auth = No
client NTLMv2 auth = Yes
client lanman auth = No
client plaintext auth = No
ldap server require strong auth = Yes
allow dcerpc auth level connect = No


I set loglevel=10 to try to see if there was some error at the
exact time the packet got processed, but besides
"set_remote_arch: Client arch is 'WfWg'" I wasn't able to see anything
relevant.

The windows client show (from program manager):
"<STOP> This device does not exist on the network."

(from command.com: net use x: \\server\share)
"Error 55: This resource does not exist on the network."

Thank you.

Andrea Baldoni