If any of you have your Mac sitting on a network with other PC users, you may know how frustrating it can be to share files through Samba. While the /etc/smb.conf file that Apple provides is useful, setting-up an effective public share requires some tweaking. I could not find the necessary tutorial on how to solve my problems on this site or elsewhere, so I decided to write this hint once I figured out how to get things working they way I wanted them to.

This hint has been tested with OS X 10.4.2 only, so I don't know if this will work or is helpful on other systems, though I imagine it is. It would be worth knowing if the backup config file, /etc/smb.conf.template, is significantly different for different versions of OS X.

Looking at /etc/smb.conf, the configuration file for Samba, you will notice among others, [global] settings and a [home] share, which usually do not require changing. There is also a [public] share commented-out with semicolons. If you remove the comment notation (and have Windows sharing turned on in the Sharing System Preferences, of course), then you will be able to connect to the specified directory with a blank user name and password.

To do this, edit the file as root (sudo pico /etc/smb.conf) and remove the comments from the following lines:

;[public]
;   path = /tmp
;   public = yes
;   only guest = yes
;   writable = yes
;   printable = no

On my computer, I changed the listed path from /tmp to the public folder in my main account. To test your share locally, type Command-K in the Finder and connect to smb://localhost/public. When you are asked to authenticate, leave both the user name and guest name blank. Hit enter and voila! Hopefully you will see whatever directory you chose to share as a mounted network connection on your desktop.

With this setup, however, you won't be able to connect to your public share from a Windows machine. Running \\hostname\public on an XP box won't let you authenticate with a null username. Simply typing "guest" for a user name or "unknown," the guest account used by Samba, also won't work. (For your information, "unknown" is a real account that has no privileges, no shell account and no password, as you will soon see.)

The simplest fix for this problem, and the meat of this hint, is to make the following changes to smb.conf. Comment out the only guest = yes line, and add the following underneath:

valid users = @unknown, @guest
guest ok = yes

The @ symbol forces Samba to look in NIS and Unix user directories, as opposed to the default location. Excluding this symbol keeps the user names from authenticating properly.

These changed settings will allow Windows users to enter "unknown" as a user name and to connect to your public share. However, for the less than technically-savvy Windows user, this may seem confusing or dumb. There is probably no "guest" account on your system, but if you would like to use "guest" as a user name in place of "unknown," you can create it; otherwise you may remove , @guest from the above line of smb.conf.

To create the guest user, open the Netinfo Application in the Utilities folder.

Carefully (very!) and without making any other changes, duplicate the "unknown" user under "users" after authentication. Change the details of "unknown copy," replacing every occurrence of -2 with -3, and replacing unknown with guest. Don't forget to scroll down to check for all fields. Save your changes and agree to update the database only if you haven't made any mistakes.

Like before, test your Samba share locally and try using "guest" and/or "unknown" as your user name without a password. If you can connect without any errors, then you've taken one more roadblock out of the way of your XP friends from connecting to your machine.