workshop contents


activists and organizers use the internet all the time—to post pictures, to collect information from folks who come to meetings, to plan actions. but many of us don't know how the internet actually works or who holds power to control the flow of data across the network.

packet sniffing is a small way to take a peek under the hood at the very big system that is the internet.

exercise: build the internet

  1. break out into groups
  2. each groups gets a deck of the tactical tech internet infrastructure cards
  3. spend some time laying out the cards according to how you think a website gets to your computer
  4. come back together and let's discuss: how did this feel? did you know more or less than you thought?


the collection of files—from style files, scripts, images, and plain text—that you request from the server and that are ultimately rendered on your computer by your browser.


the device that forwards, or routes, data packets along to where they’re supposed to go based on the addresses in the packet headers.


the computer that hosts websites and makes them publicly available through a URL. the server responds to client requests.

any computer can be both a server or client—it just depends what role the computer is playing. is the computer serving files or requesting files?

when people use the metaphor of 'the cloud' to talk about file storage, they're talking about a server or just "another person's computer."

internet service provider

there are many kinds of internet service providers, but in this case we're talking about access providers. these are the companies that install cable in your neighborhood and often supply your router when you set up your internet in your home. ISPs hold a lot of power because they physically control the flow of data.

for example, whistleblower mark klein described how the NSA was collecting internet communications by interfering in an ISP's physical infrastructure.

ISPs are also allowed to sell our browsing data to private companies.

filling out the big picture

the submarine cable map

“Most people probably don’t know that 99 percent of all transoceanic data traffic goes through undersea cables, and that includes Internet usage, phone calls and text messages.” —NYU professor Nicole Starosielski in Newsweek, 2015

peter garritano's photos of carrier hotels in lower manhattan


ingrid burrington's internet infrastructure field guide


the tiny picture

requests and responses

packet structure and headers


sniffing packets

open up herbivore! make sure you're on your own network and have the consent of folks you'll be sniffing.

😱😱😱 what is all this stuff? 😱😱😱

you're looking at the network view. it has two main parts:

  1. a diagram
  2. a table

the visualization shows all the devices that access the internet via the router—that device at the top. the table has more information about each device.

the number under each device icon is its private IP addressprivate IP addresses are dynamically assigned by the router each time a device connects to it.. IP addresses are always structured as four sets of three numbers, separated by periods.

the private IP addresses in the visualization correspond to numbers in the IP column in the table underneath the visualization. each device has its own row in the table.

it's easy to find the MAC addressMAC addresses are "media access control" addresses, unique identifiers assigned by manufacturers of networking devices and etched right onto the device itself. the MAC address follows a strict naming format which is set by the IEEE, so that networked devices can communicate with each other. of your device (there's an arrow pointing to it).

if you double-click your own device in the table, you get to the sniffer view, where you're watching your own packets come and go.

“A distinction is made between names, addresses, and routes... A name indicates what we seek. An address indicates where it is. A route indicates how to get there. The internet protocol deals primarily with addresses.” Internet Protocol Specification, 1981

keep learning

you can find a running list of links about digital/media justice, digital security tools, wireshark demos, packet sniffing journalism, and more here.


surya mattu, tom igoe, and ingrid burrington for teaching me most of what i know about the internet.