samba - Sep 1999 - Hangup while accessing Samba from NT4 W/S

Running Samba 1.9.17p4 under Linux RH5.0 (a little old, I know, and we
will be upgrading before too long, but that's the way it is right now). 
The network (actually two subnets multi-homed in the Linux machine)
consists of the Linux machine, several W95 machines and several NT4
Workstation machines. 

My problem is that the NT4 machines hang up for a while (approx 15 secs) 
under certain circumstances when accessing shares on the Samba server. For
instance, when I log in to an NT machine, it connects to three shares,
each one taking approximately 15 seconds to complete the connection. 
Also, when I access files or printers on the Samba machine from MS apps
(e.g. Word) there is a period of inactivity (15 secs again) before
anything happens. 

Once the connection has been made to the share, Win32 character mode
programs run from the command prompt on the NT machines do not suffer from
the problem. 

Also the W95 machines do not suffer from the problem.

My suspicion is that it is attempting some kind of authentication when it
hangs, but I haven't been able to track it down.

Any ideas?

------------- smb.conf -------------

[global]
   interfaces = 192.168.63.1/24 192.168.64.1/24
   workgroup = troika
   os level = 255
   local master = yes
   domain master = yes
   preferred master = yes
;   debug level = 3
;   domain logons = yes
;   logon script = %U.bat
   security = user
   wins support = yes
   printing = bsd
   printcap name = /etc/printcap
   load printers = yes
   guest account = docs
   log file = /var/log/samba
   lock directory = /var/lock/samba
   share modes = yes
   create mode = 0664
   directory mode = 0775
   hide dot files = yes
   browseable = yes

[homes]
   comment = Home Directories
   browseable = no
   read only = no

[printers]
   comment = All Printers
   browseable = no
   printable = yes
   public = no
   writable = no
   create mode = 0700

[docs]
   comment = Troika Doc Files
   path = /home/docs
   public = yes
   writable = yes
   printable = no
   only guest = yes

[magma]
   comment = Magma Master
   path = /home/magma
   public = yes
   writable = no
   printable = no
   only guest = yes
   fake oplocks = yes

[cdrom]
   comment = CD-ROM
   path = /mnt/cdrom
   public = yes
   writable = no
   printable = no
   fake oplocks = yes

[zip]
   comment = ZIP Drive
   path = /mnt/zip
   public = yes
   writable = yes
   printable = no

-- 
Bob Firth <firth@troika.demon.co.uk>
Troika International
1 Little Mount Sion, Tunbridge Wells, Kent TN1 1YS, UK
Phone: +44-1892-543373   Fax: +44-1892-545585