1<HTML> 2<HEAD> 3<TITLE> Samba meta FAQ: About the CIFS and SMB Protocols</TITLE> 4</HEAD> 5<BODY> 6<A HREF="Samba-meta-FAQ-2.html">Previous</A> 7<A HREF="Samba-meta-FAQ-4.html">Next</A> 8<A HREF="Samba-meta-FAQ.html#toc3">Table of Contents</A> 9<HR> 10<H2><A NAME="s3">3. About the CIFS and SMB Protocols</A></H2> 11 12<P> 13<A NAME="CifsSmb"></A> 14</P> 15 16<H2><A NAME="ss3.1">3.1 What is the Server Message Block (SMB) Protocol?</A></H2> 17 18<P>SMB is a filesharing protocol that has had several maintainers and 19contributors over the years including Xerox, 3Com and most recently 20Microsoft. Names for this protocol include LAN Manager and Microsoft 21Networking. Parts of the specification has been made public at several 22versions including in an X/Open document, as listed at 23<A HREF="ftp://ftp.microsoft.com/developr/drg/CIFS/">ftp://ftp.microsoft.com/developr/drg/CIFS/</A>. No specification 24releases were made between 1992 and 1996, and during that period 25Microsoft became the SMB implementor with the largest market share. 26Microsoft developed the specification further for its products but for 27various reasons connected with developer's workload rather than market 28strategy did not make the changes public. This culminated with the 29"Windows NT 0.12" version released with NT 3.5 in 1995 which had significant 30improvements and bugs. Because Microsoft client systems are so popular, 31it is fair to say that what Microsoft with Windows affects all suppliers 32of SMB server products.</P> 33<P>From 1994 Andrew Tridgell began doing some serious work on his 34Smbserver (now Samba) product and with some helpers started to 35implement more and more of these protocols. Samba began to take 36a significant share of the SMB server market.</P> 37 38 39<H2><A NAME="ss3.2">3.2 What is the Common Internet Filesystem (CIFS)?</A></H2> 40 41<P>The initial pressure for Microsoft to document their current SMB 42implementation came from the Samba team, who kept coming across things 43on the wire that Microsoft either didn't know about or hadn't documented 44anywhere (even in the sourcecode to Windows NT.) Then Sun Microsystems 45came out with their WebNFS initiative, designed to replace FTP for file 46transfers on the Internet. There are many drawbacks to WebNFS (including 47its scope - it aims to replace HTTP as well!) but the concept was 48attractive. FTP is not very clever, and why should it be harder to get 49files from across the world than across the room? </P> 50<P>Some hasty revisions were made and an Internet Draft for the Common 51Internet Filesystem (CIFS) was released. Note that CIFS is not an 52Internet standard and is a very long way from becoming one, BUT the 53protocol specification is in the public domain and ongoing discussions 54concerning the spec take place on a public mailing list according to the 55rules of the Internet Engineering Task Force. For more information and 56pointers see 57<A HREF="http://samba.org/cifs/">http://samba.org/cifs/</A></P> 58<P>The following is taken from 59<A HREF="http://www.microsoft.com/intdev/cifs/">http://www.microsoft.com/intdev/cifs/</A></P> 60<P> 61<PRE> 62 CIFS defines a standard remote file system access protocol for use 63 over the Internet, enabling groups of users to work together and 64 share documents across the Internet or within their corporate 65 intranets. CIFS is an open, cross-platform technology based on the 66 native file-sharing protocols built into Microsoft� Windows� and 67 other popular PC operating systems, and supported on dozens of 68 other platforms, including UNIX�. With CIFS, millions of computer 69 users can open and share remote files on the Internet without having 70 to install new software or change the way they work." 71</PRE> 72</P> 73<P>If you consider CIFS as a backwardsly-compatible refinement of SMB that 74will work reasonably efficiently over the Internet you won't be too far 75wrong.</P> 76<P>The net effect is that Microsoft is now documenting large parts of their 77Windows NT fileserver protocols. The security concepts embodied in 78Windows NT are part of the specification, which is why Samba 79documentation often talks in terms of Windows NT. However there is no 80reason why a site shouldn't conduct all its file and printer sharing 81with CIFS and yet have no Microsoft products at all.</P> 82 83 84<H2><A NAME="ss3.3">3.3 What is Browsing? </A></H2> 85 86<P>The term "Browsing" causes a lot of confusion. It is the part of the 87SMB/CIFS protocol which allows for resource discovery. For example, in 88the Windows NT Explorer it is possible to see a "Network Neighbourhood" 89of computers in the same SMB workgroup. Clicking on the name of one of 90these machines brings up a list of file and printer resources for 91connecting to. In this way you can cruise the network, seeing what 92things are available. How this scales to the Internet is a subject for 93debate. Look at the CIFS list archives to see what the experts think.</P> 94 95 96<HR> 97<A HREF="Samba-meta-FAQ-2.html">Previous</A> 98<A HREF="Samba-meta-FAQ-4.html">Next</A> 99<A HREF="Samba-meta-FAQ.html#toc3">Table of Contents</A> 100</BODY> 101</HTML> 102