Hey guys and welcome back. So the next thing that we have to understand for the purposes
of the L-PIC 2 objectives is the general concept behind the Network Manager utility. Now quite
honestly if you happen to be using a modern Linux based system chances are that the network
configuration happens to be handled by this very utility Network Manager. So realistically we
actually have a particular daemon and it is called well Network Manager all one word. Now what
this daemon actually does it simplifies the process of network configuration. It allows things to be
handled automatically but when you have to make a particular configuration change and that change
may be related to maybe your Wi-Fi connection or your Ethernet connection you will be able to make
this change like I say any simplified way without unnecessary complication. Now we can actually
install a Network Manager. Let me show you how we just used to do it install network hyphen manager
and we'll hit enter type in my password. There we go. I'll say yes. Now when we happen to have
Network Manager installed we're going to have access to a particular tool called NMCLI the
Network Manager command line interface and this is going to allow us to be able to easily inspect
information relating to our networking devices as well as to make particular changes to those
devices as well. So check this out. Let me show you some of the commands that we can use. We could
say NMCLI and just say the word dev for device. If I hit enter we get this nice short truncated
output relating to our networking interfaces. So we can see here on the left we see the device
which in this case is my Ethernet interface. We can tell it is an Ethernet interface because the
type tells us this right here. We know the state is connected and we actually have a connection
name here wired connection one. We also can see that we have our L O device. This happens to be a
look back interface and this is unmanaged. Now if we actually want to see more detailed information
we could say NMCLI device show now if I hit enter we're getting a lot more information say for
example here we have one block here this relates to my Ethernet connection and then the same type
of information is available for the look back interface. So if we happen to look at this one
here we can see the name of the interface. We can see the type. This is similar to what we just
saw before but notice now we can also see the MAC address relating to this interface. We can see
the MTU configuration. We can see the connection name as well as our IP address or actual gateway.
We have our routing configuration such that we can see a default route i.e. if we do not have a
particular route this will match all destinations and our next hop will be indeed 192.1680.1
which happens to be our default gate. We simply put the root configuration is that for any routes
we do not know what to do with just send it to the default gateway. We can also see we have DNS
configuration here one server and below we have a second server as well as IPv6 information as well
and if we look on down similar information is available for our look back interface. Now another
command we can do is NMCLIcon. This is going to allow us to see our active Ethernet interface. We
get the name but this also presents to us the UUID the universally unique identifier for this
particular interface connection. Now the fact that we happen to see this name we can actually use
this name and make changes to that particular interface. Say for example like I say we wanted
to pull this interface down. What I could do is say sudo because we're going to make an actual
change we need super user privileges I'll say NMCLI and then I will say con but as opposed to just
hitting enter here instead what I'm going to do is I'm going to specify the command down to bring
the particular interface down. Now what interface do I want to bring down? I want to bring down
wired connection one which we can see right here. So within my inverted commas I will say wired
connection one and if I hit enter what is going to happen is that this interface is going to drop
and this is the interface to which I am connecting to over SSH. So now we can see here my SSH
connection has been terminated. So what I'll do is I'll go to the actual machine open this up
log in and I'll go directly to the terminal. So now what I'll do is I'll say sudo NMCLIcon up this
time I'll type in the same name wired connection one and hit enter I'll have to type in my password
of course there we go. Now we can see here on the right hand side the connection has been
reestablished. So using the NMCLI tool will allow us to invoke network manager which can handle and
simplify our network configurations. Now if we want to get hands-on and make manual changes we can go
in using this tool and by using the NMCLI command we can easily display the status of our network
interfaces or if we so choose we can make modifications quite easily using this tool via
the command line and alter the state of our network connections. This may be our ethernet
connection this may be be our Wi-Fi connection using the NMCLI tool we're going to be able to have
full control over all of those type of connections. So really for the purposes of the LPIC2 examination
we want to understand the existence of the network manager utility as well as its basic
functionality and role in controlling or networking on our Linux devices. So I hope this has been
informative for you and I'd like to thank you for viewing.