Hello, everyone.
And in this video we are going to see the nmap MTU
scan. So MTU stands for maximum transmission
unit.
This particular scan is something similar
like our previous scan, which
was the fragment scan.
How it is similar?
We can decide the number of fragments that
we want to send in a packet
while sending a particular request to our
Target.
So NF is giving the option to the user to set a
specific MTU to the packet. There is a similar to
the packet fragmentation technique that we have explained earlier remember?
You can specify hyphen.
MTU
but you need to give the MTU that
is the maximum transmission unit in the
multiples of 8, so you can give it off 8 16
24 32 Etc.
You can specify the empty MTU of
your own choice with the command - MTU and
the number that you want to give followed by
the Target IP address.
So, let's see how you can run this
particular scan and you can specify your
own MTU.
t on my
screen the nmap M2 IP address scan wherein
I can see that MTU is
written in the multiples of 8. The
command is nmap - MTU. I'm going
to choose 24 MTU this
time.
So I will just paste it over here and I'm going
to scan these specific ports and I'm choosing the ethernet
adapter to scan which is eth0.
Perfect, as you can see, I have started the scan
successfully.
In the Wireshark, you can see the scan has been running and
if we see the packets over here.
Let's have this particular request is for Port 22.
This is for Port 80 Port 23 again, Port 22.
and
here we have seen the
Status of the ports are filtered, but we
are interested in seeing that MTU that
we have sended the MTU that was sent was 24. So,
let's see what MTU has been received. So
as you can see over here, the MTU has
been received of 24 bytes.
Which says that we have successfully able to
send our own fragment, but the
machine had discarded that particular fragment
and we are not able to identify the right
status of the port. That's why and map
has got the response that all the ports that
we scanned are filtered.
In case there is a firewall running and in
the firewall takes this malicious send
it fragments.
Of the MTU then it will respond correctly and
we will be able to identify the port
state.
I hope you guys understood how you can use a MTU scan
with nmap. Thank you.