rawnet lightning talk 'how the internet works
TRANSCRIPT
How The Internet Works
What Is The Internet?Decentralised global network of computers
Created by the US Defence Department’s Advanced Research Projects Agency in the 1960s
Lots of serviceshttp, ftp, smtp, ssh
Common protocol: TCP/IP
Loading A WebsiteGive me www.rawnet.com please
Sure - here you go
What Does It REALLY Ask For?Open a socket to the server
Send a request for a URL, optional headers
GET / HTTP/1.1Host: www.rawnet.comConnection: keep-aliveAccept: text/html,application/xhtml+xml,application/xml;q=0.9,image/webp,*/*;q=0.8User-Agent: Mozilla/5.0 (X11; Linux x86_64) AppleWebKit/537.36 (KHTML, like Gecko) Chrome/48.0.2564.97 Safari/537.36Accept-Encoding: gzip, deflate, sdchAccept-Language: en-GB,en-US;q=0.8,en;q=0.6
How Does It Get There?DNS
IP addressing
Routing
DNS - Domain Name SystemInternet addressing uses numerical addresses
People use words
DNS maps words to numerical addresses hierarchy
Recursive lookup
Lots of caching
DNS Recursion
IP AddressesIPv4 - four parts 0-255
e.g. www.rawnet.com is 23.235.43.249
232 (4,294,967,296) addressesalready run out
NAT allows sharing and address re-use192.168.0.1
192.168.0.2
192.168.0.3
109.176.68.202
Private
192.168.0.1
192.168.0.2
192.168.0.3
Private
114.181.67.85
IP AddressesIPv6 - formalised 1998
128 bit address: 2128 addresses340,282,366,920,938,463,463,374,607,431,768,211,456
enough for an address for every atom on the surface of the Earth, and still have enough addresses left to do another 100+ Earths
Routing
Routing
A Word About CDNs
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