This has nothing to do with smb.conf. All remote users need to be added to the smbpasswd file in addition to the standard UNIX /etc/passwd file.
For example, to create a user named 'joe' that can access files via Samba, run this command: adduser joe smbpasswd -a joe -- Impossible to make share folders accesible and writable without using modyfing config files. https://launchpad.net/bugs/51344 -- ubuntu-bugs mailing list ubuntu-bugs@lists.ubuntu.com https://lists.ubuntu.com/mailman/listinfo/ubuntu-bugs
