Hi, welcome to section six net CAT penetration test.
In this video we're going to talk about scanning a network or troubleshooting
any problem in a network. When we are looking for a problem,
a good way to start this search is about to get a broad examination of the
problem and then be more precise.
In the first step to troubleshooting a problem in a network,
we could start by executing a scan in some hosts to check if
the host is on and if some services are running or not.
Our first impression is to verify if a port services is open or not.
Netcat can help in this task because Netcat keeps things simple.
Netcat does not alter the data stream between the communication
with the systems.
That means that Net CAT does not do not send traffic control comments
during the transmission of data.
This could mis spread the communication because of some
special characters. For example,
net CAT does not inject or react to data session between two systems.
So you can use it extensively knowing that the data stream will
remain uncorrupted. The idea is to use Net CAT for scanning.
For troubleshooting the network
for scanning net CAT can use some options.
We have the dash V for ity dash N for
numerically only. Internet protocol IP address dash z.
That's mean that no data will be passed to the receiver dash w v
detail. Cat. How long to wait for a port to scan?
Remember that net Cat will tell you the service associated in a specific port.
It's mean that in this folder,
in this path for Windows and for Linux net Cat,
use the the services defined in this file to show
a specific service running in a specific port. When analyzing host,
we can use a range of ports or specify individual ports for our
scanning. For example,
we can use a range in this example or we can use a specific ports for
our scanning port In this case,
if we are troubleshooting a particular services and checking if the port
of the service is closed,
we could say that there is a problem in the server and not with the network
because the service is not running because any port is
closed. So in our Carlin environment here,
we can use Netcat for our troubleshooting examination.
We saw that the first step for troubleshooting is to verify if Port
is open or not. So these, uh, port is open or closed.
That's mean that the problem is, is not,
is in the server and is not in the network.
So I have a server in my network, my local network here.
So we can use Net CAT to check if some ports are available, are open or not.
So we are gonna use net CAT option V
for verbose mode Z. That's mean to, it's not to connect,
it's only to verify for if the port is open or not.
W v to put a output for our comment and one
that's mean that the output will be for one second.
Second and enter the host now. So my local host here is
1 9 2 1 8 0 1
and we saw that we can use a specific port or a range
of ports. So now I use a range of port check.
If enter in this list of port, which ports are available,
are open or not. So I use the port 1 2 9.
So the net cat,
we start a list and for each port we try for one second.
So now we saw that we have uh, 80 a TT P open.
Remember that all the how Net CAT discover and associate
the name for each port so that there's a a default path
folder,
dash ADC dash services for that's mean.
Let's have a bind, a binding for a port and a service name.
So this is how Net CAT knows and put the,
the specific name for each port net cat is finished. The,
the scanning and net CAT use the highest port
number to begin.
So this how this why that get used in 19 and going
down. Okay, for the low port,
for example for Sonet, ftp, this port, I'll close it.
Great. That's it. That's mean that for this range here that I use it,
the ports that are open is the 18 for http
and the port 53.
So we can check uh, for a specific port for example, we,
we'll repeat this in common,
but now I put 80 for the port and that's it.
The port is open or we saw that the port 53 is open.
53 it's open to,
so we can use these both options for a specific port or a
range of ports. And for the same result we could use for example,
N map and use N map and use the same strategy
to check the port.
So we use net cat here because net cat is very simple, uh,
is very, is more fast for example for result.
But for example, it's only to check in map.
Here I use the same host in net map,
identify the same ports, the same port, the same stats,
and the same service that net get net five before and map
here. Get an another port here, a high port. Okay.
Uh,
but the same ports that use it in the for specific port or for a range of port
is the same result of Netcat.
And you saw that netcat was more fast than end map in this case.
So Netcat is a good tool and a fast tool to to
verify which ports are open or not.
In this video we saw how to use Netcat to scan a network
and start ARU process. In the next video,
we'll a look at testing network latency. Hope.