Everything sent over the Internet from one computer to another is sent as digital data. This data is chopped into short sections and packaged with the information needed to send it to its destination. If this data is packaged in such a way that every packet must be received, or resent it is usually known as a packet. For example a web page or a form submission will be sent as packets.
If this data is sent as a continuous stream of packages they are usually known as datagrams, and are not resent if they don't get to their destination. For example video being streamed over the Internet.
This data is not sent directly from one computer to the destination computer, but through a network of computers known as routers. Each router will read the destination address for each packet, check the fastest route, and send the packet on to the next router on the route, until the packet arrives at its destination.
Your office or home will have a router that connects all the computers on your home network to the routers of your Internet service provider ( ISP)
These networks of routers offer many different routes between your ISP and the ISP that supplies the destination for your message, or the server that is sending you a web page.
We can get examples of these routes between our computer and a different computer on the Internet by using software known as 'Traceroute'
I am using the traceroute command on my Linux Ubuntu computer
We can also get a rough idea of the physical location of this route by looking up the physical location information and plotting it on a map.
Copy the results from your traceroute window and paste it into the mapper page
This will display a map of the routers that identify their location.
This demo will run out of lookups if too many users use my key from ipinfo.io, but you can also sign up and get your own free key.
Note that if you use my key then ipinfo reports back to me with details of what has been looked up.
If a criminal or an intelligence organisation is able to control any of these routers they can copy the information about the source and destination of these messages, and also copy the contents of each data packet.
A wifi hotspot is particularly easy to compromise in this way, and criminals may set up free and open hotspots in public places just so that they can snoop on the traffic. At this point all the packets in a message are going through the same point and so are particularly easy to put back together in the correct order. Once out on the Internet backbone the packets in a message may go by many separate routes and are harder to collect. However many nations restrict the links between the Internet inside that nation and the Internet outside it just so that all packets entering and leaving can be monitored and controlled.