Lecturer: In this lesson,
we're going to discuss a lot of the different types
of Remote Access options that you may be supporting
as a network technician or network administrator.
These different methods will allow a client
to access a server,
or a network device remotely over your network.
Now, as an administrator,
you're going to be using some of these methods
to reach into the command-line interface of your routers,
your switches, and your firewalls as well,
in order for you to be able to modify their settings
and configurations as part of your job functions.
Now, there are many ways to access this data remotely,
and you can also control these devices remotely as well.
So in this lesson,
we're going to discuss Telnet,
SSH, RDP, VNC, and TTY.
Now, the first thing we need
to talk about with remote access technology is Telnet.
Now, Telnet operates on Port 23,
and Telnet is used to send text-based commands
to remote devices,
and it's considered a very old networking protocol.
Everything you do in Telnet is going to be text-based.
And here, you can see that I'm connecting over Telnet
to rainmaker.weatherunderground.com.
By doing this,
I can then look up the daily weather for my area.
Now, one of the biggest drawbacks using Telnet
is that it sends everything over the network in plain text
or unencrypted formats.
Now, in this case,
I really don't care that I'm sending things in plain texts,
because the only information I have to send to the server
is the three-digit airport code
for the city that I want to check the weather with it.
But if I'm going to send something private
like my Social Security number,
or my password or my credit card number,
then I would never ever want to use Telnet for that.
Remember, Telnet should never,
never not ever be used for anything when you're connecting
to one of your secure devices,
anything like a router or a switch or a firewall.
Because when you're configuring them,
everything would be set in plain texts,
including your commands,
your username, your passwords,
your access control list,
and all of that stuff.
Instead, we always want to use
an encrypted text-based remote access technology,
something like Secure Shell.
This brings us to our second remote access technology
which is Secure Shell.
Now, Secure Shell or SSH,
is going to operate over Port 22.
Secure Shell is also known as SSH,
and it works just like Telnet.
But it's going to encrypt everything that's being sent
and received between the client and the server,
the router or the switch that you're communicating with.
Therefore, you're going to have much better security
when you're using SSH,
than when you're using Telnet.
Remember, anytime you need to connect to a networking device
to configure it in the command-line interface,
you should always be doing this over SSH using Secure Shell.
This will ensure you have an encrypted connection
to that device.
The third remote access technology we need to discuss
is known as RDP,
or the Remote Desktop Protocol.
Now, the Remote Desktop Protocol operates over Port 3389,
and it's a proprietary protocol developed by Microsoft
which provides the users with a graphical interface
to connect to another computer over a network connection.
While RDP is not really useful if you're trying to talk
to a router, a switch or a firewall,
it is really useful when you're trying to remotely access
and control a Windows server or client machine.
For example, if your SEAM,
or network management system operates on a Windows machine
you can RDP into it
as a way to connect to it over your local area network.
RDP is going to provide you
with a graphical user interface known as a GUI or GUI.
This allows you to access a server and desktop
and control it using your mouse and keyboard.
Now, when you're remotely connected to this machine
it's going to act just as if you were sitting in front of it
but you could do it from across the network
or across the world.
For example, here,
you can see there are three devices
and they're all connecting to a Windows 7 machine.
You have a Macintosh laptop,
you have an iPad or an Android tablet,
and you have a cell phone.
And all of these are able to reach in
and do the communication using RDP,
just as if I had a mouse
and keyboard sitting right in front of that workstation.
RDP is going to allow you to connect to these devices
from across your network
or across the world,
depending on how you have it configured.
Now, the Remote Desktop Protocol itself
is not considered to be a secure protocol.
Instead, you need to secure that connection
by using something else to tunnel it over.
For example, you can use a remote desktop gateway or RDG
to create a secure connection between you
and that gateway and then tunnel into the RDP session.
Or you can use a VPN like a virtual private network.
Speaker: The fourth remote access technology we need
to discuss is known as VNC.
VNC or Virtual Networking Computing operates over Port 5900
and it was originally developed
for the thin client architectures
and things like virtual desktop infrastructure or VDI.
VNC operates a lot like RDP,
but unlike RDP,
which only operates on Windows clients and servers,
VNC is truly cross-platform.
And therefore, it can be used on Linux,
OSX and Windows clients.
This brings us to our fifth
and final remote access technology known as TTY
or a Terminal Emulator.
Now, a Terminal Emulator is any kind of software
that replicates as TTY input or output functionality
that we use to remotely connect to a device.
The TTY is really the terminal or endpoint
for communication between the computer
and the end user.
And it handles all the text input
and output between the user
and the Shell or the command-line environment.
This Terminal is going to be used to accept input
and display the output.
Whereas, the Shell or command-line environment does
the actual processing.
This is called the TTY,
because that was originally what it was used for.
Originally, when we had computers working as mainframes back
in the 1970s and 1980s,
there was a device called a teletype.
And the teletype was actually used
to connect to the mainframe
and be able to issue those commands
and then display back the output that was generated
by the command-line environment within that mainframe.
And this is why a Terminal Emulator
is often referred to as a TTY or a teletype device,
because that's what it's being used to emulate,
going back to those early days of computing.
Now, if you're using a Linux or Unix system,
you'll often see their terminal environments called TTYs
when you're referring to each individual different one
on that particular server or machine.