I have just used Filesys::SmbClient with smb2 or 3. You just need to fill in the file ~/.smb/smb.conf that Filesys::Smbclient autocreates with something like this:

[global]
client max protocol = SMB3
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I verified this using wireshark traces.

Did you try to configure that option in your ~/.smb/smb.conf?

[global]
client max protocol = SMB2

That is a bit embarrassing: I changed the general smb.conf in /etc/samba, the user didnīt have one. But then I created it and added the global parameter (client max protocol) and something changed! Now the connection is actually established, as far as I can see though I still get an error:

map_errno_from_nt_status: 32 bit codes: code=c0000059
smbc errno NT_STATUS_REVISION_MISMATCH -> 22
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Google has failed me on my first try but I now have something I can work on. Maybe you also know about the new error but in any case - thank you a lot Anonymous Monk!

It may or may not be related, but libsmbclient seems to have (had) some peculiarities regarding the smb.conf file, as commented on in the module:

  # Actually libsmbclient will segfault if it can't find file
  # $ENV{HOME}/.smb/smb.conf so I will test if it exist,
  # and create it if no file is found. A empty file is enough ...
  ... creation of an empty $ENV{HOME}/.smb/smb.conf
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So maybe libsmbclient does not crash nowadays but doesn't necessarily respect /etc/smb.conf if it doesn't find a local file.

Yes, I have set the global parameter in smb.conf. And it did cause the smbclient call to work without adding the max-protocol tag (-m), so this was successful:

smbclient -U domain\\user //HOSTNAME/ShareName -c "dir"

But unfortunately it has no effect on Filesys::SmbClient and my Perl-script. It appears that it still uses SMB1 (same error message as before). I am very puzzled over this behaviour.

Filesys::SmbClient doesn't have any knowledge of the protocol flag. I've gone ahead and fixed this in my environment (since I just had scheduled transfers fail because of it). I've supplied the patch here. I make no guarantees, I've done minimal testing, and I'm not responsible for anything that this patch may break in your environment. -- Jeremy Baumgartner

--- SmbClientParser.pm.orig     2018-05-11 10:55:54.033252684 -0500
+++ SmbClientParser.pm  2018-05-11 11:07:15.612066151 -0500
@@ -5,6 +5,9 @@
 # Copyright 2000-2002 A.Barbet alian@alianwebserver.com.  All rights 
+reserved.

 # $Log: SmbClientParser.pm,v $
+# Revision 2.7.1 2018-05-11 11:06:00 jjb0528
+# - Added protocol selection to the options for smbclient
+#
 # Revision 2.7  2004/04/14 21:53:18  alian
 # - fix rt#5896: Will Not work on shares that contain spaces in names
 #
@@ -83,6 +86,7 @@
     $self->Password($ref{password}) if ($ref{password});
     $self->Workgroup($ref{workgroup}) if ($ref{workgroup});
     $self->IpAdress($ref{ipadress}) if ($ref{ipadress});
+    $self->Protocol($ref{protocol}) if ($ref{protocol});
     $self->{DIR}='/';
     $self->{"DEBUG"} = 0;
     return $self;
@@ -99,6 +103,7 @@
 sub Password {if ($_[1]) {$_[0]->{PASSWORD}=$_[1];} return $_[0]->{PA
+SSWORD};}
 sub Workgroup {if ($_[1]) {$_[0]->{WG}=$_[1];} return $_[0]->{WG};}
 sub IpAdress {if ($_[1]) {$_[0]->{IP}=$_[1];} return $_[0]->{IP};}
+sub Protocol {if ($_[1]) {$_[0]->{PROTO}=$_[1];} return $_[0]->{PROTO
+};}
 sub LastResponse {
   if ($_[1]) {$_[0]->{LAST_REP}=$_[1];} return $_[0]->{LAST_REP};}
 sub err {
@@ -498,17 +503,19 @@
 # rearrange_param
 #--------------------------------------------------------------------
+----------
 sub rearrange_param {
-  my ($self,$command,$dir, $host, $share, $user, $pass, $wg, $ip) = @
+_;
+  my ($self,$command,$dir, $host, $share, $user, $pass, $wg, $ip, $pr
+oto) = @_;
   if (!$user) {$user=$self->User;}
   if (!$host) {$host=$self->Host;}
   if (!$share){$share=$self->Share;}
   if (!$pass) {$pass=$self->Password;}
   if (!$wg) {$wg=$self->Workgroup; }
   if (!$ip) {$ip =$self->IpAdress; }
+  if (!$proto) {$proto =$self->Protocol; }
   if (!$dir) {$dir=$self->{DIR}; }
   my $debug = ($self->{DEBUG} ? " -d".$self->{DEBUG} : ' -d0 ');
   $wg = ($wg ? ("-W ".$wg." ") : ' ');      # Workgroup
   $ip = ($ip ? ("-I ".$ip." ") : ' ');      # Ip adress of server
+  $proto = ($proto ? ("-m ".$proto." ") : ' ');      # Protocol
   $dir = ($dir ? (' -D "'.$dir.'"') : ' '); # Path
   # User / Password
   if (($user)&&($pass)) { $user = '-U "'.$user.'%'.$pass.'" '; }
@@ -519,7 +526,7 @@
   if ($host) {$host='//'.$host; $path.=$host; }
   if ($share) {$share='/'.$share;$path.=$share; }
   $path.='" ';
-  my $prefix = $self->{SMBLIENT}.$path.$user.$wg.$ip.$debug;
+  my $prefix = $self->{SMBLIENT}.$path.$user.$wg.$ip.$debug.$proto;
   return ($self, $command, $prefix, $dir);
 }
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Welcome to the monastery, Netras! Have patience, some knowledgeable monk will help you eventually.