How the Internet works, part 2

Security matters

• Telnet is from the era of the free and open internet

• Free and open to packet sniffers like tcpdump, that is!

    sudo tcpdump -A -n -s0 -i en0 port 80
  

• Secure protocols and SSL

    [winpty] openssl s_client -connect www.somesite:443
  	
    GET / HTTP/1.1
    Host: byzantini.st
  

• What it looks like when you try to packet sniff SSL

The Hypertext Transfer Protocol (HTTP)

• The components of a URL: protocol, host, port, path(, query, fragment)
• What happens when you run Jupyter?
• Connecting to an HTTP server
• HTTP request verbs
  • HEAD
  • GET
  • POST
  • PUT
  • DELETE
• HTTP headers
• HTTP responses
• How to make an HTTP request in Python