- [Instructor] Secure Shell is a protocol
to allow encrypted remote console access over a network.
This is most closely associated
with connecting to a Linux server,
router or switch for configuration.
It uses TCP port 22 for reliable delivery of packets.
Though, it is most closely associated with Linux servers,
Microsoft announced in 2015 that moving forward,
Windows Server will have native support for SSH.
It was originally designed to be a secure replacement
for plain text methods like Telnet.
SSH uses public key cryptography via certificates
to verify remote computers,
and public or private certificate can be generated
and installed, or as is most often the case,
the server will just generate its own certificate.
Authentication of usernames is often done via accounts
on the server being logged into
or via a centralized authentication system
for better control.
Beyond remote access, SSH has some additional features.
It supports tunneling,
which allows you to securely send traffic
over an SSH session.
An admin can securely transfer files
using SSH file transfer, more often known as SFTP.
While SSH is native to most systems,
additional programs are often necessary
on a Windows machine.
PuTTY is an open source SSH client
that also supports SSH tunneling.
WinSCP is also open source and provides SFTP access.
Version one of SSH was released in 1995.
It was released as freeware initially,
and eventually evolved
into a pay-to-play proprietary system.
In 1999, developers took the most recent open source version
of SSH and began to develop and improve it.
This project became known as OpenSSH
and is still the widest deployment footprint
of any open source SSH implementation.
Version two is unfortunately incompatible
with SSH version one.
It boasts both security and feature improvements.
It's likely the bulk of your network configuration
and server administration will be via this protocol,
so it's best to familiarize yourself with it now.