LAB: netcat and some of its friends

Remember nc time-server 13 from the wireshark assignment? We're going to play a little more with nc. It's fun, and some comfort with nc will come in very handy during the next couple weeks.

Setup

You're going to want two terminals, preferably but not necessarily on separate hosts. For example:

A Kali terminal in a VM and a Terminal on macOS
A Kali terminal in a VM and a WSL terminal on Windows
Two Kali terminals in the same VM :(
Two macOS Terminals :(
Two WSL Terminals :(
...

Make sure both terminals have nc installed.

Make sure at least one terminal has python3 installed.

Make sure one of your hosts has Wireshark installed

A simple chat

For the rest of this document, I'm going to call one of your terminals "host1", and the other "host2". For my personal setup, host1 will be Kali in a VMWare VM, and host2 will be my macOS machine, but your setup will be whatever you choose.

Determine the IP addresses of host1 and host2
Run nc in listening mode on host1: nc -l -p 5000 (if you're listening on a macOS terminal, use nc -l 5000)
On host2, make a connection with nc HOST1_IP 5000 from host2 to host1
Type some text on host1; type some text on host2; take a look at both
Ctrl-C on host2. What happens on host2? What happens on host1?
Repeat the process, but Ctrl-C on host1.
Fire up Wireshark on host1, set its collection filter to "host HOST2_IP". Take a look at the traffic.

Variations with nc

Transfer a file from host1 to host2 by doing nc -l -p 5000 > destination_filename on host2 and cat filename | nc HOST2_IP 5000 on host1
Transfer a file from host2 to host1
Set up the host2 listener to send specific text back to host1 as soon as the host1 client connects to the listener
Set up the host1 connector to send specific text to the listener on host2, and then quit when connecting

Easy web server with python

On host1, cd to some working directory with a random file or two in it.
Run
python3 -m http.server 8888
On host2, run
curl http://HOST1_IP:8888/
Same thing, but with
curl -v http://HOST1_IP:8888
Can you download a file from host1 to host2?
Can you download a file from host1 that's not in the working directory of the python3 command?

Your Carleton user name, lower case:

For the Chat, the listener was on host1. Can you do the same thing in reverse, with the listener on host2?

Is port 5000 special? Can you use a different port for these exercises?

What protocol does Wireshark show for the Chat communications?

Are the Chat packets encrypted? Why or why not?

Can you do the Chat thing between your own computer and a classmate's computer? What happens when you try?

Describe briefly what is happening when you do nc -l -p 5000 > destination_filename (on host2) and cat filename | nc HOST2_IP 5000 (on host1).

If you use Wireshark to watch the curl/python3 interaction, what do you see?

Can you use nc instead of curl as your client for the python3 web server? How?

Any questions?