user mapping in samba

Dear all,

Our system has been running Samba-4.2.2 for some years.
It was built from source, and configured as a workgroup file server & domain controller (see attached smb_conf.txt).
The daemons "nmbd -D" & "smbd -D" are invoked on start-up.

We're going to upgrade the software to the latest Samba-4.9.1 (also built from source with the same parameters for the "configure" script).
The build was successful, but we encounter a problem in testing the installation.

The Samba server contains a user "SMBUSER".
On a Win-7 client (computer name = CLIENT, workgroup = WKGRP) logged on as an administrator "WINUSER", executing the command

net use X: \\SERVER\Share

returned an error :

Enter the user name for 'SERVER': SMBUSER
Enter the password for SERVER:
System error 86 has occurred.

The specified network password is not correct.

However, the command works fine for Samba-4.2.2.
By comparing the level 4 logs, it appears that Samba-4.9.1 produced incorrect user mappings (see attached 4.2.2.log & 4.9.1.log).

The test was then repeated but with workgroup name added to the username :

Enter the user name for 'SERVER': WKGRP\SMBUSER
Enter the password for SERVER:
The command completed successfully.

The results imply that Samba-4.9.1 (or some earlier version) has changed the authentication mechanism.

We'd like to know how to restore the old behaviour ?

You can map users in Linux by choosing user map option in /etc/samba/smb.conf file and create the file that you pointed it to. The file should be a text file containing entries in the following format :
!<server user> = <client user>

For example,
!Dave = SDave

This specifies that the client user "SDave" will map to the server user "Dave" on the server.

If you want to learn more Samba techniques visit Linoxide. It is a great online tool and platform to learn Linux basic and advanced commands with examples.