- [Instructor] Server Message Block
is an application layer protocol
for sharing files, printers, and serial ports.
It can run directly on TCP port 445,
which is how it's most often used.
It can also run on Legacy NetBIOS,
but is seldom seen doing so.
It's the best known as the mechanism
behind Windows file sharing.
SMB 2.0 was released in 2006 with Windows Vista.
The supposed chattiness of the protocol was reduced.
They took the volume of commands from over 100 to just 19.
Multiple commands can be submitted in a single request
further increasing efficiencies.
The block size was also increased from 16 bit to 128 bit
in some cases which improves performance
in large file transfers.
SMB 2.1 was introduced with Windows 7 and Server 2008 RC2.
This brought some performance enhancements.
SMB 3 shipped with Windows 8 and Windows Server 2012.
This too saw additional performance boosts
as well as some new functionality.
Additional security enhancements were seen,
including end-to-end encryption,
was also introduced using AES Signing.
SMB 3.1.1 was introduced with Windows 10
and Windows Server 2016.
Additional encryption support was added
and it also implements a pre-authentication integrity check.
If it determines that a client is SMB 2 or greater,
it makes secure negotiations mandatory.
There's also an open source implementation known as Samba.
This allows Linux devices to act
as both SMB clients and servers,
and in some instances,
they can even operate as a Windows domain controller.
Virtually every network or system admin
will use or facilitate the use of SMB sharing
as sharing is one of the main advantages of any network.