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IP version 4, which you will
commonly see written as IPv4,
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is the primary protocol
for almost everything
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that we do on today's networks.
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If you're communicating
between two different devices,
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IP addresses will be used
on both of those devices.
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There's a newer version of IP
called IP version 6 or IPv6.
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And you'll find that most
major operating systems now
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support both IPv4 and
IPv6 on those systems.
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These are the IP
addresses on my device.
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I have both IPv4 addresses
and IPv6 addresses
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that have been assigned
to my computer.
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This means that I can
communicate to any other device
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on the internet, either
using IPv4 addresses or IPv6.
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IPv4 addresses are
four separate numbers,
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all separated with a period.
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So an example of an IPv4
address would be 192.168.1.131.
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We can also view this
in a binary form.
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You can see there are 32
total bits in an IPv4 address.
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And they're separated into
these four different blocks.
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This is the binary
representation of 192.
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This is the binary
representation of 168,
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and so on.
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You'll sometimes hear these
referred to as 8-bit segments,
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one byte, or one octet.
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And having four
of those together
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is 32 total bits or 4
bytes of an IPv4 address.
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If you were to convert this
binary value back to decimal,
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you would see that
11000000 is 192.
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This also means if we
have eight of these bits
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and they're all set to 1, the
maximum value would be 255.
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So any of these
groups or octets can
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have a maximum value of 255.
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We quickly realized with the
popularity of the internet
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that we were going to
exceed the capacity of what
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IPv4 addresses could provide.
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So we created IPv6 which
was a new form of IP that
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had a much larger address.
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You can see that an IPv6
address is 128 bits in length.
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This means that you can
have a very large number
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of total addresses,
which ultimately means
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that the $6.8 billion
people on Earth
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could have a very large
number of addresses
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for each individual person.
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This gives us enough addresses
to assign an IPv6 address
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to almost anything
that we might use.
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You can see that IPv6
addresses are separated
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into eight different groups.
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And each one of those
groups consists of 16 bits.
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This is also two
bytes or two octets.
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Instead of displaying these
addresses as binary or decimal,
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you can see that in IPv6,
we choose to address
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these in hexadecimal format.
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So a common IPv6 address might
be FE80 colon colon 5D18 colon
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652 colon CFFD colon 8F52.
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As you can tell, it's
a much larger address.
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And in some ways, it's a
much more difficult address
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to try to memorize.
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For that reason,
your DNS is going
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to be a very important tool
to use on your network,
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because you'll very often be
referring to these servers
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by their name instead of
their very long and relatively
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complicated IPv6 address.
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We also tend to see
IPv6 addresses assigned
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with a 64-bit subnet mask.
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That means that the first 64
bits are the network address,
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and the last 64 bits
are the host address.
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If you're assigning an
IP address to a device,
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there are a number of important
configuration parameters
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you need to add.
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The first would obviously
be the IP address itself.
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So for IPv4, you might assign it
an IP address of 192.168.1.165.
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Every device on your network
needs a unique IP address.
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So you have to
make sure there are
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no duplicates when you
start assigning these IP
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addresses to devices.
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Along with the IP
address, we also
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need to assign a subnet mask.
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This will normally be assigned
by the network administrator.
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And it's usually a
format like this one,
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such as, 255.255.255.0.
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Subnet masks are used
by the local device
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to determine what subnet
it happens to be a part of.
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So it uses this to mask out
the IP address, leaving only
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the host address at the end.
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You'll often be provided both of
these values at the same time.
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So if you're assigning
an IP to a device,
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someone may tell you
to assign 192.168.1.165
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with a subnet mask
of 255.255.255.0.
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If you only have one
of these parameters,
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you won't be able to complete
the IP address assignment.
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Both of these parameters
are used in conjunction
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with each other.
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And you have to have both
of them to assign an IP.
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If the device also needs
to communicate outside
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of your local subnet,
and most devices do,
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you'll need to also
assign a default gateway.
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This is the IP
address of a router
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that allows you to communicate
outside of your local subnet.
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So the default gateway in
this particular example
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is 192.168.1.1.
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In most cases, this
is the bare minimum
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of configurations you would need
to assign to a local device.
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So you would need an IP address,
a subnet mask, and a default
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gateway.
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As I mentioned earlier, the
domain name system server
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or DNS server is also
an important component.
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We don't commonly type an
IP address in the browser
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that we're using.
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Instead we type
www.professormesser.com
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or www.google.com.
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It would be very
complicated if we
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had to remember all of these
IP addresses and type them
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in manually every time we wanted
to visit one of these websites.
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Instead, we have a service
that does this for us.
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It converts between these
names to an IP address.
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This is because the routers and
other devices on our network
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don't know what
these names mean,
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but they do know where to send
your traffic if there's an IP
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address associated with it.
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So we need something
that can translate
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between the fully
qualified domain
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name, such as
professormesser.com,
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to an IP address.
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And it's the DNS server that
provides that translation.
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We would commonly configure
a DNS in the IP settings
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of your operating system.
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So in my particular case,
I've assigned 8.8.8.8.
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You'll also notice there
are other DNS servers listed
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on my machine.
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That's because DNS is
such a critical resource
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that it's very common to assign
two separate DNS IP addresses
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to your configuration.
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That way if one DNS
is not available,
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you have another DNS
that you can use.
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In my example, I have 8.8.8.8
and 8.8.4.4, both of which
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are DNS servers
managed by Google.
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