Hello, my name is Stephanie, and in this lecture you will learn how to discover open ports with Nmap.
In the realm of network reconnaissance, one of the most valuable tasks is to determine the port states
of a target.
This process is commonly known as port scanning, so Nmap, the versatile network scanning tool, excels
at this task, so providing a valuable insights into the running services on a target.
So in this segment we will explore essential Nmap options related to port scanning and learn how to
effectively list open ports on a target segment.
One.
Launching the default scan to initiate a default scan with Nmap.
All you need to is the target information, which can be an IP address hostname or even a network range.
So let's take a look at this example here.
So Nmap could easily.
Dot com.
So here this command will initiate a scan on the target host Qatar Telecom and provide detailed information
about the open ports and their corresponding services.
And here it is, the output here.
And as you can see, Tron 988 filtered TCP ports and so on.
So you will also learn what is here.
So in segment two, which is.
Segment two, so you will understand the scan results here.
So the scan result generated by Nmap offer a crucial information about a target host.
Let me actually open the grommet here and I will draw things on the screen to explain this better.
So here.
Here we have alongside with the IPv4 and IPv6 addresses, reverse DNS names and latency details.
The results highlight the ports and their respective states, and the port states are categorized like
this here.
So in first year we have open.
Open ports.
This this here in open here.
As you can see, all of these ports are open here.
So with this we are indicating so Nmap is indicates that a service is actively listening for connections
on the port open here.
And also we have the closed.
With this here.
Nmap indicates to us that the probes were received, but no service was detected on the port.
And we also have the filtered.
Filter it.
So this indicates that the probe's reception could not be determined possibly due to the filtering mechanisms.
And we also have on filtered.
So with this here, iMap indicates us that the probes were received, but the state couldn't be established
and we also have open filter it here.
This means that indicates that the port appears to be either open or filtered, but the state couldn't
be determined.
And we also have the.
Klaus filtered here, which indicates that the port appears to be either closed or filtered, but the
state couldn't be determined.
And here we will also learn the.
How to customize Nmap scans.
So while the default scan provides a valuable information, Nmap offers a plethora of customization
options.
So for instance, for instance, you can specify alternative DNS server using the DNS servers option
like this DNS servers option to control DNS resolution during the scan.
For example, this Nmap DNS server here and we will enter the Google DNS here one eight, eight eight
here.
And after that comma we will type and 8.8.94.4 here and now we will do console.com.
So by providing this DNS server, Nmap will utilize this servers for hostname resolution and here further.
Furthermore, Nmap performs host discovery to determine if the target is online before conducting port
scanning and you can skip the host discovery step using the pen option here.
After Nmap p an uppercase and lowercase n here.
And here you will see another result.
It might.
It might take here.
Actually, let me use the sudo here.
Sudo enter password.
That's it.
And here this command will directly indicate initiate port scanning without prior post discovery with
uppercase and lowercase n options here.
And here Nmap employs various tick scan techniques depending on the user's privileges, and the default
scan can utilize a synchronized scan, stealth scan or TCP connect scan here so these techniques ensure
comprehensive port scanning while considering the user's pillages and network environment.
So port scanning with Nmap unravels the network services running on a target, enabling us to gain insights
into potential vulnerabilities and secure our networks by understanding the scan results here, customizing
the Nmap scans and being aware of the underlying scan techniques so we can effectively explore open
ports and their associated services here.
Now, as you can see, we are seeing services FTP, Smtp, FTP domain, Http, Pop3, iMap and so on.
So equip yourself with Nmap port scanning progress and unlock the secrets hidden within your network.