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- [Instructor] Secure Shell is a protocol

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to allow encrypted remote console access over a network.

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This is most closely associated

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with connecting to a Linux server,

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router or switch for configuration.

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It uses TCP port 22 for reliable delivery of packets.

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Though, it is most closely associated with Linux servers,

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Microsoft announced in 2015 that moving forward,

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Windows Server will have native support for SSH.

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It was originally designed to be a secure replacement

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for plain text methods like Telnet.

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SSH uses public key cryptography via certificates

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to verify remote computers,

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and public or private certificate can be generated

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and installed, or as is most often the case,

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the server will just generate its own certificate.

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Authentication of usernames is often done via accounts

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on the server being logged into

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or via a centralized authentication system

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for better control.

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Beyond remote access, SSH has some additional features.

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It supports tunneling,

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which allows you to securely send traffic

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over an SSH session.

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An admin can securely transfer files

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using SSH file transfer, more often known as SFTP.

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While SSH is native to most systems,

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additional programs are often necessary

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on a Windows machine.

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PuTTY is an open source SSH client

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that also supports SSH tunneling.

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WinSCP is also open source and provides SFTP access.

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Version one of SSH was released in 1995.

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It was released as freeware initially,

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and eventually evolved

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into a pay-to-play proprietary system.

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In 1999, developers took the most recent open source version

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of SSH and began to develop and improve it.

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This project became known as OpenSSH

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and is still the widest deployment footprint

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of any open source SSH implementation.

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Version two is unfortunately incompatible

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with SSH version one.

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It boasts both security and feature improvements.

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It's likely the bulk of your network configuration

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and server administration will be via this protocol,

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so it's best to familiarize yourself with it now.