The package ‘samba-client-4.6.16+git.169.064abe062be-3.46.1.x86_64’ provides smbclient and smb.conf.
Samba’s online docs
[INDENT][/INDENT]https://www.samba.org/samba/docs/current/man-html/smb.conf.5.html#CLIENTMAXPROTOCOL
say this
[INDENT]Normally this option should not be set as the automatic negotiation phase in the SMB protocol takes care of choosing the appropriate protocol.
The value default refers to SMB3_11.[/INDENT]
Applying this advice to SLES12 is detrimental; even though this version of samba-client does support SMB 3.1.1, without this directive, the default value is used, which in SLES12’s case is ‘NT1’, which isn’t compatible with the modern world.