Hey guys, welcome back. This is the last video in the networking module. I just want to give
you guys the tools you need to further your knowledge of networking in general,
and how networking tasks would be performed on Linux. So, there is one more tool that
I want to introduce you guys to called "nmap" So, nmap is an abbreviation
for the term network mapper, and it's an open source tool that can tell you what
devices are on the network, what IP addresses are in use, and what services each
machine is offering. So, let's go ahead we need to install the tools so let's run "sudo
apt-get install nmap" and it's going to download about 3 megabytes of data and it's
going to expand to 18 megabytes.
Alright, now that this is installed the way we're going to use this is by simply
typing and "nmap" and then we can do a bunch of things after this. So, the first
thing we're gonna cover is how to scan specific IP address, so I wanna get the
IP address that I have so I'm gonna run "ifconfig"
So, "nmap 192.168.0.100 and we can see what ports are
open,
well we can see what ports are available, their state, and then also the service
that they provide by name. So, I have Apache installed on this machine, you guys
should have it installed on yours as well, if you went through the Apache
videos and so you should see the same thing here. And so the port is 80, the
state is opened because we've got we've got Apache running right now, it
automatically runs
when start up the machine, and the service that the port provides is http. So, if I
were also running an SSH server on this machine you would see another entry in
this list for port 22, it would say state open, and service SSH or something
to that effect. Now, if we want more information we can run "nmap -v"
then the IP address again, so "192.168.0.100" "-v" means verbose and what verbos
mode does in most applications is it also, aside from the regular output, it also
gives you more direction on what's happening in the application or provides
more information than you would normally get, so in this instance
we see that it's doing a bunch of scans. It scans the IP address then for 1,000 ports
and it finds all these ports that are open, and then also finds a bunch of a
bunch of closed ports listed here,996 closed ports, and it it gives us the same
output as before. So, that's neat, I only have one device on my network actually except
for my router. Now, my router I believe is 192.168.0.1
So, that is the IP address for my router, so what we can do is
scan multiple IP addresses at a time in multiple ways. So,
the first way that we're gonna do is by specifying each IP address. So, let's go
ahead and run "nmap 192.168.0." and then we're going to add the last values
in here
separated by comma.
So, first I'm going to scan my machine as well as the router and if I had a
network address of 192.168.0.10 I could also do that, but I dont so i'm
not going to. Now, what we see here would be my router. We can see this
is the IP address for it and this is what services it offers
on which ports, and then we get my machine right here that
provides the same output as it does before but this is how it would output
multiple machines scan results. Now, you can also scan a range of IP address. So,
let's go ahead and run nmap command again
192.168.0.1-100 this is gonna go from 1 all the way to a 100 and
it's gonna scan all IP addresses within that range, so if I had a bunch of machines
on my network, which I actually do I have my phone on that network as well, and
that's it actually so I've my router, my computer, and my phone. My phone is not
coming up so I'm not doing anything on my computer right at the moment, I'm just
checking what IP address I have on my phone here, if I can find out how. Ok, so
the IP address on my phone is .101, so I'm what gonna do is run the previous command
and just have it scan from 1-101. We should see three machines come up, I
don't think my phone has any services or open ports that it would
list, but let's have a look here.
And when you scan multiple IP addresses the more you ,the longer it takes.
Okay, so there's nothing available from my phone coming up. Now, you can also
scan, so when we talked about IP addresses we
discovered that you can use anything from 0 to 255. So, if I were to want to
scan all IP addresses that begin with 192.168.0, I could then put this in here, right,
but rather than doing that we can actually use a wild card here. And, I'm
actually gonna cancel this because it's gonna take a while.