From Technologia Incognita
Jump to: navigation, search

Lectures at Hacking Feminism

Fist lecture in this series:


  • Empower each-other with knowledge
  • Learn the basics technical concepts of underlying Internet works
  • Discover & emphesise roles of women
  • Practice & get our hands dirty
  • Work on the alternatives together!
  • Personal goals: learn by teaching; develop series of lectures; practice practice practice!
  • What's your goals?

Internet Plumbing

Internet Plumbing is a word-game with multiple layers of meaning (ha! a recursive pun ;-)

Squirrel eating cable.jpg

Internet As a Series of Tubes

Ubiquitous and complicated as plumbing?

  • Internet as a utility
  • just like "plumbing" (water & sewage), there is underlying "technology" to it, so complex, that no-one seems to grasp how all of it works
  • 60% of the population of the planet does NOT have "teh Internets", and 30% does not have plumbing either (
  • Mary Midgley: "Utopias, dolphins, and computers - problems in philosophical plumbing "

Women role models in computing.jpg

Women's role

Participate, take action, join

  • contribute to this wiki page
  • learn more!
  • join mailing lists discussions for technical policy development & Internet governance
  • learn to code & take part in FLOSS community
  • join a hackerspace
  • teach your skills to others
  • contact me: BECHA @ xs4all dot nl // @Ms_Multicolor


Internet is network of networks 

Step by step


Local networks

  • "Small network" -- computers "talking" to each other
    • Local Area Network = LAN
    • With cables (ethernet), or Wireless (WiFi)
    • How do they find each other? using unique numbers: MAC (ethernet) address (layer 2), translated by ARP (MAC to IP address)
750px-Ipv4 address.svg.png

IP addresses

  • About IP (Internet Protocol) addresses
    • binary numbers, written as decimal (IPv4) or hexadecimal (IPv6)
    • Can be "public" or "private" (=local)
    • What is the format?

Exercise!! (ifconfig)

  • Typical / mainstream home (or small office) network
    • Private IP addresses
    • NAT = Network Address Translation - translated from multiple private to (usually) one public IP address
    • Home router is (usually) a gateway, firewall, and NAT box at the same time
    • ... and because of IPv4 exhaustion there is also double-NAT aka NAT444        -  (10/8 prefix)      -  (172.16/12 prefix)     - (192.168/16 prefix)


Where do they come from.png

  • Where do the IP addresses come from?
    • Hierarchical distribution (see charts)
    • Principles: fairness, aggregation, conservation, registration
    • Used to be "needs based", now open to "market forces"
    • Policies for distribution ("rules") are developed in open, transparent, bottom-up process
    • IPv4 is "legacy", has run out - but is still DE FACTO THE ONLY STANDARD in use!


Inter-connecting and Routing

  • Connecting "to the Internet"
    • usually through commercial ISP (Internet Service Provider): dial-up, fibre, ... modem or router.
    • "free Wifi"
    • over mobile!
    • alternatively: community-mesh-peer-to-peer : MeshNet
Judith: Release Brian!
Pilates: I shall... "welease" "Bwian"!
Guard: Where is Brian of Nazareth? I have an order for his release.
Brian: ... You stupid bastards!
Joker: Uh, I'm Brian of Nazareth.
Brian: What?
Joker: Yeah, I'm Brian of Nazareth.
Guard: Take him down.
Brian: I'm Brian of Nazareth!
random slave: I'm Brian!
Another random slave: I'm Brian!
Rich merchant: I'm Brian, and so's my wife!
Guard (pointing to Joker): Take him away and release him.
Joker: No, I'm only joking. I'm not really Brian.  I'm only pulling your leg. It's a joke! I'm not him!
Guard (hits him) 
Joker: Bloody Romans. Can't take a joke.


Exercise!! (ping) & Video!!! ( (Youtube taken over / hijacked by Pakistan Telekom)

  • Relationships between "providers"
    • direct peering: between more-less same size & same "importance" ISPs
    • usually at IXP (Internet eXchange Point, e.g. Ams-IX, LINX...)
    • "buying transit" from a "national Telco", usually
    • large providers and carriers create a "backbone"

Video!!! "Internet Revealed, a movie about IXPs"

Domain Name System

500px-An example of theoretical DNS recursion-nl.svg.png
  • How do humans find services on the Internet? -> BY NAME!
    • numbers (IP addresses) are translated to names by DNS
    • web-sites, servers, services have DNS "names"
    • hierarchical distribution of names
    • Advanced concepts: resolver, cashing, primary & secondary name-servers, master-slave, recursive resolver, labels, zones, A & AAAA records

  • DNS with NAT
Network Address Translation (file2).jpg





  • youtube hijack
  • How IXP's work
  • Net of Rights

Want to learn more?

Networking Principles

Protocol stack hourglass 1.jpeg


  • packets & packet switching
  • encapsulation
  • layered network model
  • (open) protocols & (open) standards
  • end-to-end principle
  • ports
  • server/client architecture
  • cryptography

Networking-fig3.jpg Email-tmp3163.jpg

Tcpip pat.gif

Comparing OSI & TCP / IP layers

Original borrowed from:

TCP / IP Model OSI Model
Layer OSI Layer Protocol data unit (PDU) Function Examples
Application 7. Application Data High-level APIs, including resource sharing, remote file access, directory services and virtual terminals TLS, FTP, HTTP, HTTPS, SMTP, SSH, Telnet, BGP!
6. Presentation Translation of data between a networking service and an application; including character encoding, data compression and encryption/decryption CSS, GIF, HTML, XML, JSON
Transport 5. Session Managing communication sessions, i.e. continuous exchange of information in the form of multiple back-and-forth transmissions between two nodes RPC, SCP, NFS, PAP,
4. Transport Segment (TCP) / Datagram (UDP) Reliable transmission of data segments between points on a network, including segmentation, acknowledgement and multiplexing NBF, TCP, UDP
Network /
3. Network Packet Structuring and managing a multi-node network, including addressing, routing and traffic control AppleTalk, ICMP, IPsec, IPv4, IPv6
2. Data link Frame Reliable transmission of data frames between two nodes connected by a physical layer IEEE 802.2, L2TP, LLDP, MAC, PPP, ATM, MPLS
1. Physical Bit Transmission and reception of raw bit streams over a physical medium DOCSIS, DSL, Ethernet physical layer, ISDN, USB

Cross-layer functions:

  • ARP is used to translate IPv4 addresses (OSI layer 3) into Ethernet MAC addresses (OSI layer 2).
  • Domain Name Service is an Application Layer service which is used to look up the IP address of a given domain name. Once a reply is received from the DNS server, it is then possible to form a Layer 3 connection to the third-party host.
  • etc


Many many more resources: books, videos:


Wonderful site for teaching Internet concepts to children:


RIPE NCC Glossary:

  • TCP/IP
  • IPv4, IPv6: Internet Protocol (IP) addresses
  • NAT: Network Address Translation
  • DNS: Domain Name System
  • ASN: Autonomous System Number
    • used for BGP routing (Border Gateway Protocol)
  • IXP: Internet eXchange Point
  • SMTP
  • HTTP
  • CDN

Advanced topics

Layers as an allegory

Osi-layers-ti-shirt-download.jpeg Evi nemeth.jpg
The art of engineering.png

Left: OSI Model T-shirt enhanced to include an 8th and 9th layer as defined by Evi Nemeth: // (old, broken link -> )

(TODO: add ISC reference to Evi's wikipedia page!!)

Right: back of the T-shirt from the IETF75 in Stockholm, 2005



Explaining complex concepts using layers is a useful abstraction.

Goal here is to illustrate layers by practical examples, and point out owners, developers, dangers, mitigations & alternatives.

This is not exactly technically correct, for the detail oriented people! 
Number Layer name Example Practically Owner Developed by Vulnerabilities / Dangers Mitigation / Securing Alternatives
9 Organisation / Political (Internet) Governance technical community, civil society, governments IGF (Internet Governance Forum), UN, ITU, IETF, ICANN, awareness, take part! someone will build a new *net, AlterNet :-)
8 Individual / Financial Operating System (OS) + choice of software Linux, FreeBSD, Minix...; iOS, Android, Windows... User! programmers & developers: FLOSS community;
Apple, Google,Micro$oft
backdoors, surveillance, spying on users; lock-in; monopoly; community participation; unionization of programmers; see articles here [yy] knowledge, self-empowerment, solidarity
7 Application 7.3 -> VoIP skype
7.2 -> SMTP email
7.1 HTTP: web, WWW web sites! LoLCats! individuals, on their own servers!
blogs (blogspot?), mainstream media, hosting companies; CDNs (Akamai, Amazon...); corporations: Google, Facebook, Twitter... YouTube..
W3c, IETF censorship; silos; walled gardens; commercialization, consumerism; technically: httpS, SSL, TLS; Tor;
politically: activism, digital human rights; associations of users;
torrent! p2p! alternative social media!
6 Presentation HTML, CSS, JSON
5 Session BGP (actually layer 7...) routing: exchanging AS reachability info via gossip: based on trust & peering agreements!
physical routers by routers: Cisco/Juniper (commercial monopolists ;-)
Large ISPs; Tier1 / Tier2 ; IXPs!! RIRs give out AS numbers "routing-wg" @ RIPE; *NOGs! (nano, nlnog, grnog; peering forums; Euro-IX); IETF; Open-Source community ; hackers "route hijacks", government regulation & takeover (killer switch), hierarchies; technically: BGPsec, IRR, RPKI;
politically: influencing governance
p2p protocols, Betman [xx]; MPLS, SDN; Tor?!
4 Transport UDP -> e.g. DNS (see above!) User; Registrar, Registry, ccTLD, gTLD, ICANN, US government! DNS OARC, IETF, root-nameserver operators, ICANN, IGF/UN/ITU "balkanisation", US hegemony; internationalization; censorship; technically: DNSSEC, DANE ; Tor;
politically: participating in governance
Alternative trees; blockchain (namecoin); etc
3 Network Internet / IP ifconfig; IPv4, NAT,, IPv6 no-one: IP addresses are "leased"!
RIR PDP, IANA, IETF hierarchy, run-out, incompatibility, market forces; surveillance IPSec Blockchain? GSM? Radio?
2 Data-link MAC addresses, Ethernet device drivers, WiFi drivers licensed to users Broadcom, Realtech, INTEL.. patents, closed source, Intellectual Property Laws open source SW, open HW  ?!
1 Physical Network connections Ethernet cables, WiFi antennas, fibers, satellites, satellite dishes, base-stations, under-sea cables  ; POTS (old-fashioned phones -> BBS, dialup) Individuals
communities, ISP, "carriers", corporations, governments,
commercial companies, governments
"ownership" models; hierarchy of server-client model; pollution & distraction of Earth; surveillance commoning; shared infrastructure; development of sustainable technologies (?!), recycling; awareness & activism Community WiFi, Project Loon, Drones
HW - end user equipment Computer, tablet, phone... User Commercial companies: Apple, Siemens, Samsung... Un-ethical manufacturing, security backdoors, pollution caused by e-waste disposal, Hard: Open HW movement; fair-phone; DIY, Repair Cafes, fair-trade...

Security, Privacy, Avoiding Censorship


MeshNet: "Hackers and philosophers building an utopia together":




November 2014: Nature will have the last word, on Future of Technology, RIPE69

UnCivilization: critical thinking about Internet & capitalism:

Playfull: Internet Simulator:

  • Alternative Network Deployments: Taxonomy, characterization, technologies and architectures

Next topics

Internet Governance

See this lecture : Internet_Governance_Digital_Culture#Internet_Governance


Traceroute Much?


Linux Install Fest!

Lectures to be made in the future





Other resources for learning

  • "Internet in a Bottle"


/5G =