Just to make sure that you know what to do, let's do a quick overview of IPv4 networking
before starting this lesson about networking.
This is only intended to be a short summary of all the required elements.
I'm expecting most to have already knowledge about networking in general.
So what do we need in order to configure a server on a network?
Well, you need an IPv4 IP address.
Is that really so?
Well, honestly, no, because internally Linux is using IPv6 as a default network protocol.
But it happens to be even if IPv6 was already introduced in the mid-1990s, most environments
are still using IPv4.
So you will need an IPv4 address.
So each node has its own IP address, which is written in dotted decimal notation, like
192.168.4.200.24.
You can manually assign these IP addresses, but in many networks, DHCP server, which stands
for Dynamic Host Configuration Protocol, is used to automatically hand out these IP addresses.
In the IP address, there's a subnet mask.
The slash 24 is a subnet mask.
And it indicates that the first three digits in the address, in this case, 192.168.4, is
the network part.
And the last digit is the node part of the address.
Then there's the default router.
Default router, also known as the gateway, specifies which server to forward packets
to that have an external destination.
It's a mandatory component, because without a default router, you'll never get outside.
Now, the default router should always have an address that starts with the same network
bytes as your local address.
So if your local address is 192.168.4.200, and your default router is set to 192.168.1.1,
then something is wrong, because they are not on the same network.
Make sure default router is always on the same network.
Last, there's the DNS name server.
The DNS name server is the IP address of a server that helps to resolve names to IP
addresses and the other way around.
Without DNS, you would need to address every server on the internet by using its IP address.
That's not very human-friendly, and that is why we have domain name system, where you
can use DNS names instead of IP addresses.
As I mentioned, IPv4 is still the most common IP version, but IPv6 addresses can be used
as well.
And IPv6 addresses are written in hexadecimal notation.
In the next lesson, you'll learn a bit more about them.
But one example would be FD01, colon, colon, 8EBA, colon, 2, 1, 0.
That's a valid IPv6 address.
IPv4 and IPv6 can coexist on the same network interface.
Even stronger, if you look at your network configuration, you will see that your network
configuration is IPv4 as well as IPv6.
Let me show you.
So for a quick overview of networking, I'm using IPA.
IPA is showing the loopback interface that's used internally for services that use IP to
communicate with one another, and there you will always find the IP address 127.0.0.1.
And also, the INET6 address, which is colon, colon, 1, slash, 128.
And then we have ENS160, which is the name of my network device here.
And on this network card, we have old names.
These are alternative names.
And most important is the INET address.
INET, that's my IPv4 address.
So I can see that I'm using 192.168.29.141, slash, 24.
And it's a dynamic address.
The word dynamic indicates that it comes from a DHCP server.
And we also have an IPv6 address.