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Cat-DNS: a DNS server that resolves everything to cats

Cat-DNS: a DNS server that resolves everything to cats

The internet needs more cats. DNS servers are the authority on all things internet. Therefore, the best DNS server is the one that resolves everything to cats. This talk is about that.

Do you think DNS is scary/arcane/confusing? Nope! I'll show you how you can write your own DNS server in less than 200 lines of JavaScript. With cats. We're going to walk through the basics and find out how DNS servers work, how you can talk to a DNS server if you're a browser, and how to talk back to a browser if you are a DNS server.

By the end, you'll know how to what a static IP is, why dig is a hilarious tool if you want to mess around with the internet, how you can write your own DNS server and perhaps most importantly, why you probably shouldn't. And have I mentioned the cats? There will definitely be cats.

Videos of this talk:
https://www.youtube.com/watch?v=qDPhW9P44fI
https://www.youtube.com/watch?v=kvwAIiledvo

Monica Dinculescu

August 01, 2014
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  1. MORE CATS
    THE INTERNET
    needs

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  2. View Slide

  3. I’M MONICA
    @notwaldorf

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  4. DNS

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  5. DNS
    domeow name system

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  6. DNS
    GOOGLE.COM ☛ 74.125.226.134

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  7. CAT-DNS
    GOOGLE.COM ☛ cats? cats!!

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  8. View Slide

  9. View Slide

  10. EVEN?
    HOW DOES
    it

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  11. UDP
    USER DATAMEOW PROTOCOL

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  12. UDP
    it’s the honey badger

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  13. 8.8.8.8

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  14. 8.8.8.8
    800,000 rEq/sec

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  15. 8.8.8.8
    70 billion rEq/day

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  16. 8.8.8.8
    avg: 45 ms

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  17. CAT-DNS
    avg: 7 ms

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  18. CAT-DNS
    but only knows cats

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  19. so basically

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  20. www.images.google.com?
    YOU DNS

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  21. www.images.google.com?
    YOU DNS
    images.google.com
    TTL: 5 minutes
    ip: 74.125.226.104

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  22. DOMAIN Name Server
    RNS
    www.images.google.com?
    YOU

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  23. Recursive Name Server
    RNS
    www.images.google.com?
    YOU

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  24. RNS
    www.images.google.com? I DON’T KNOW BUT I CAN ASK
    YOU

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  25. ROOT
    RNS
    images.google.com?
    ROOT NAME SERVER
    YOU

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  26. ROOT
    RNS
    .com .org .biz
    I KNOW THE TLDS
    YOU
    images.google.com?

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  27. ROOT
    RNS
    .com
    ASK THE .COM SERVER
    YOU
    images.google.com?

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  28. ROOT
    RNS
    .COM
    YOU
    images.google.com?

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  29. ROOT
    RNS
    .COM
    I’M GETTING HUNGRY
    YOU

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  30. ROOT
    RNS
    .COM
    google yahoo imgur
    YOU
    images.google.com?

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  31. ROOT
    RNS
    .COM GOOGLE
    YOU
    images.google.com?

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  32. ROOT
    RNS
    .COM GOOGLE
    authoritative
    YOU
    images.google.com?

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  33. ROOT
    RNS
    .COM GOOGLE
    74.125.226.135
    YOU
    images.google.com?

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  34. 74.125.226.135
    ROOT
    RNS
    .COM GOOGLE
    YOU

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  35. ROOT
    RNS
    .COM GOOGLE
    YOU
    yay !

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  36. View Slide

  37. CACHING
    ain’t no one got time

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  38. TTL
    time to live

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  39. browser cache
    chrome://net-internals/#dns

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  40. View Slide

  41. WORKS FOR ME
    BUT not for you…wat?!

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  42. www.whatsmydns.net

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  43. DANGER ZONE
    what can go wrong?

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  44. DANGER ZONE
    cache poisoning

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  45. ROOT
    RNS
    .COM
    images.google.com?
    YOU

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  46. ROOT
    RNS
    .COM ☢
    YOU
    images.google.com
    TTL: 10000 minutes
    ip: 66.000.000.66
    images.google.com?

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  47. ROOT
    RNS
    .COM ☢
    YOU
    trololololololol
    images.google.com?

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  48. View Slide

  49. THE RFC?
    DID YOU EVEN
    read

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  50. (no)

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  51. REALTALK
    1987 RFCS ARE PAINFUL RFCS

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  52. View Slide

  53. your cat *
    how to spy
    on
    * if your cat is a DNS server

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  54. NSLOOKUP
    use: nslookup google.com

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  55. View Slide

  56. View Slide

  57. View Slide

  58. DIG
    use: dig google.com

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  59. View Slide

  60. View Slide

  61. View Slide

  62. View Slide

  63. View Slide

  64. View Slide

  65. View Slide

  66. View Slide

  67. View Slide

  68. View Slide

  69. ❤

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  70. View Slide

  71. 9:30 am
    yay, code!
    because

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  72. “I'LL OFTEN DROP
    DOWN TO NODE.JS IF I
    REALLY NEED TO BE
    CLOSE TO THE METAL”
    - SOMEONE ON HACKER NEWS

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  73. require(‘node-bitarray’)
    !
    require(‘buffer’).Buffer
    !
    require(‘dgram’)
    !
    require(‘ip’)

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  74. var dnsServer = dgram.createSocket('udp4');
    dnsServer.bind(53,'localhost');
    !
    dnsServer.on('message', function (msg, rinfo) {
    // Parse message.
    // Transmogrify into response.
    // Resolve to cat-service OR imgur.
    // Giggle.
    !
    dnsServer.send(=^_^=);
    }

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  75. var dnsServer = dgram.createSocket('udp4');
    dnsServer.bind(53,'localhost');
    !
    dnsServer.on('message', function (msg, rinfo) {
    // Parse message.
    // Transmogrify into response.
    // Resolve to cat-service OR imgur.
    // Giggle.
    !
    dnsServer.send(=^_^=);
    }

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  76. var dnsServer = dgram.createSocket('udp4');
    dnsServer.bind(53,'localhost');
    !
    dnsServer.on('message', function (msg, rinfo) {
    // Parse message.
    // Transmogrify into response.
    // Resolve to cat-service OR imgur.
    // Giggle.
    !
    dnsServer.send(=^_^=);
    }

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  77. var dnsServer = dgram.createSocket('udp4');
    dnsServer.bind(53,'localhost');
    !
    dnsServer.on('message', function (msg, rinfo) {
    // Parse message.
    // Transmogrify into response.
    // Resolve to cat-service OR imgur.
    // Giggle.
    !
    dnsServer.send(=^_^=);
    }

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  78. var dnsServer = dgram.createSocket('udp4');
    dnsServer.bind(53,'localhost');
    !
    dnsServer.on('message', function (msg, rinfo) {
    // Parse message.
    // Transmogrify into response.
    // Resolve to cat-service OR imgur.
    // Giggle.
    !
    dnsServer.send(=^_^=);
    }

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  79. var dnsServer = dgram.createSocket('udp4');
    dnsServer.bind(53,'localhost');
    !
    dnsServer.on('message', function (msg, rinfo) {
    // Parse message.
    // Transmogrify into response.
    // Resolve to cat-service OR imgur.
    // Giggle.
    !
    dnsServer.send(=^_^=);
    }

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  80. var dnsServer = dgram.createSocket('udp4');
    dnsServer.bind(53,'localhost');
    !
    dnsServer.on('message', function (msg, rinfo) {
    // Parse message.
    // Transmogrify into response.
    // Resolve to cat-service OR imgur.
    // Giggle.
    !
    dnsServer.send(=^_^=);
    }

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  81. imgur
    how to be a cat authority

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  82. View Slide

  83. NO lessons
    some lessons
    are better than

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  84. what now?
    slow dns means less cats

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  85. what now?
    pick a faster one

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  86. what now?
    host your own? bind!

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  87. what now?
    get around geolocation

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  88. what now?
    https:// /notwaldorf/cat-dns

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  89. what now?
    STEALING WIFI JUST GOT WEIRD

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  90. @notwaldorf
    ❤

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