Update README.md

README.md

@@ -31,6 +31,11 @@ Install Vagrant, and run the VM with `vagrant up`!
   repo's directory, and then append the output to your `~/.ssh/config` file.
   You can rename the host as you like (change the first line to `Host mininet`).
   Then in VSCode you can connect to the `mininet` host.
+  
+  You can install the Python and Pylance extensions on the VM. You can add
+  `/home/vagrant/mininet`, `/home/vagrant/pox`, `/home/vagrant/openflow`
+  to the `"python.analysis.extraPaths"` settings to make code analysis work
+  properly.
 
 ## Notes
 
@@ -43,3 +48,17 @@ Install Vagrant, and run the VM with `vagrant up`!
       vagrant box add https://mirrors.tuna.tsinghua.edu.cn/ubuntu-cloud-images/focal/current/focal-server-cloudimg-amd64-vagrant.box --name ubuntu/focal64
 
 * If you don't feel like installing Vagrant, you can also spin up your own Ubuntu VM on your favorite VM provider (VMware/VirtualBox/HyperV) or even cloud provider (AWS EC2?) and run the `bootstrap.sh` script to set up Mininet. We recommend using Vagrant because it abstracts away many provider- and OS-specific nuances, which have historically troubled many students getting set up for the project.
+
+## Using Wireshark
+
+* You might need to install XQuartz (for macOS) or Xming (for Windows) for X11 forwarding.
+* To use Wireshark, first install it:
+
+      sudo apt install wireshark
+
+* As the Vagrant user, run `sudo xauth add $(xauth list $DISPLAY)` to allow `root` to use X11 Forwarding.
+  You might have to do this every time you want to run Wireshark.
+* Run `sudo wireshark &` to run Wireshark in the background.
+* Once the controller is up, you will see the interfaces (e.g. `s1-eth1`) in Wireshark. You can choose any
+  of them and view the packets it sends/receives.
+