Summary
Highlights
Paola, a software engineer at Microsoft, introduces the topic of how the internet works. She explains the historical context, mentioning Vint Cerf and Bob Kahn's invention of internetworking protocols in the 1970s, which laid the foundation for the internet.
Vint Cerf defines the internet as a 'network of networks' that links billions of devices globally. He emphasizes that the internet is a design philosophy and architecture expressed in protocols, which are sets of rules allowing devices to communicate. This adaptable design allows the internet to incorporate new communication technologies.
Vint explains that all internet devices have unique addresses, similar to phone or street addresses. This addressing system is fundamental to the internet protocol (IP). A computer's unique address is called an IP address, which is used when computers request and send information to each other.
Paola delves into the structure of IP addresses, which are hierarchical arrays of numbers represented in bits. She describes IPv4, designed in 1973, which provides over 4 billion unique addresses using 32 bits. Due to the internet's growth, a transition to IPv6 is underway. IPv6 uses 128 bits, offering an enormous number of unique addresses, more than enough for every grain of sand on Earth.
Vint introduces the Domain Name System (DNS), which translates human-readable domain names (like www.example.com) into their corresponding IP addresses. This system allows computers to connect to destination servers on the internet without users needing to memorize IP addresses. An illustrative example demonstrates how DNS servers resolve domain names.
Paola explains that DNS servers are organized in a distributed hierarchy, dividing responsibility for major domains like .org, .com, and .net. She also discusses the security vulnerabilities of DNS due to its open nature, specifically mentioning DNS spoofing. This type of cyberattack involves a hacker changing a DNS server to link a domain name to a fraudulent IP address, redirecting users to imposter websites and exposing them to further risks. Despite these challenges, both DNS and IP are designed to scale with the ever-growing internet.