Sharing Resources with Samba

What Must Be Done to Configure Samba

In Windows 95, SMB services exist as part of the Client for Microsoft Networks. In Windows NT, the Server network service (available through Control Panel/Network, Services tab) provides SMB server support, the Workstation network service provides SMB client support, and the NetBIOS Interface supplies additional necessary SMB functionality. First, ensure that these components have been installed appropriately. As SMB runs on top of TCP/IP, also ensure that this protocol is installed and bound to the Ethernet card.

On a Unix server, two daemon processes, smbd and nmbd, supply all Samba functionality.
To determine whether Samba is currently running, at the Unix command prompt type

ps ax | grep mbd | more

and verify that both smbd and nmbd appear in the process list. Start and stop Samba daemons in the normal Unix fashion:

/etc/rc.d/init.d/smb start
/etc/rc.d/init.d/smb stop

Samba supports a configuration file, smb.conf. The Samba model for customizing details such as share names, directory paths, access control, and logging involves editing this text file and then restarting the daemons. A minimal smd.conf (enough to make the Unix server viewable on the network) looks like this

 ; Minimal /etc/smd.conf

 [global]
    guest account = netguest
    workgroup = NETGROUP
 

A Word about Security

Samba supports user-level security. Version 1.9.18 added an encryption feature for user passwords that can be turned on or off. Some older Linux distributions, such as Red Hat 5.2, shipped Samba configurations having the feature available but turned off by default. When working with computers configured in this way, realize that the plain text passwords supplied when using smbclient can be easily spotted by a network sniffer.

Other Issues to Consider

Name mangling commonly occurs when transferring files between Unix and Windows computers. For example, copying a long filename from a Linux ext2 filesystem to Windows FAT filesystem can result in the file name and file extension being truncated to fit the 8.3 naming convention. Conversely, file names that are in mixed case on the Windows filesystem can become names in all lower-case when copied to the Unix system. Unix and Windows systems implement the end-of-line (EOL) convention for ASCII text files differently. Windows uses a two character carriage-return/line-feed (CRLF) sequence, whereas Unix uses only a single character (the LF). Unlike the Unix mtools package, Samba does not perform EOL conversion during file transfer. Unix text files (such as HTML pages) appear as one very long single line of text when transferred to a Windows computer with Samba.
Samba continues to improve with new releases. Version 2.0.4, for example, implemented better integration between Windows NT client security and Unix file ownership and access permissions. Version 2.2.0 added server-side access control lists (ACLs). When working with a Linux distribution, even if it is the latest such available, remember that new versions of application packages such as Samba get released independently. While it is not practical to upgrade an application each time an update appears, it is wise to watch for needed bug fixes, security patches, or specific new features.

In Conclusion

The year 2002 marks the tenth anniversary of Samba. Very few software applications have enjoyed such a long useful lifetime. Samba's resiliency testifies to its role as an essential technology when working in heterogeneous networks that include Linux or Unix servers. While Samba is not difficult to use, some detais of its configuration remain tricky.