I am writing this primarily as a reminder for myself but maybe it will be of use to you too if you ever need to see what data is being sent/received from your computer to a remote server; I keep writing the incantation down in my trusty notebook but for some reason I never seem to be able to find it again! I use tcpflow to look at what is being sent over the wire. For example, to look at the network traffic between your computer and ‘maps.google.com’, execute the following command as root:
tcpflow -c -i <interface> host maps.google.com
flag means print to the console.
It’s a useful tool and it means that I don’t have to figure out how to use tcpdump! You can download tcpflow here.