Hello everyone. So in this
video we are going to see how you can see nmap
bogus TCP UDP
checksums.
So in this scan, you are basically going to
transmit invalid TCP UDP
checksums to the Target.
And the target is basically going to respond on that
particular request that you are going to send through
and map.
Practically every host IP stack
would correctly drop the packets because of the
bad checksum that has been added with the
TCP UDP request. But if we get a
character response, then possibly the response
has originated from a firewall or IDs
that wasn't concerned with confirming the
checksum.
So, let's see how you can run this particular
scan and how you can identify if there
is a fireball enabled or not.
I'm going to type this command which is nmap the
target server that I'm going to scan and the
four port numbers which are 21 22 23
and 80 with hyphen hyphen Batson
to send the bogus TCP UDP
Jackson and the output in verbose mode.
Let us hit enter and see the output of four of
these ports.
As you can see we have got the output and in
the output we see that all the four ports
are filtered which means and map is
not able to correct correctly identify the
status of the port by sending the
bad checksums.
Let's do this scan again. And this time not
just send the bad check
some.
And you can see when I hit enter we have got the correct status
of the port.
Wherein we identify that Port 80 is open
and other ports are closed correctly The Syndicate
that this particular server is
not been installed within firewall.
If there was a firewall it could have responded
correctly for these particular
ports with bats some
I hope you guys understood. Thank you.