Before DNS

While most of name resolution solutions are long dead there are two of them still works in modern system: hosts file, NetBIOS

NetBIOS

Microsoft developed networking protocol called NetBIOS/NetBEUI. It was suitable for small network because it provided no logical addressing like IP addresses and all the broadcasting made it unacceptable for large networks.

• Flow
• To address the large installed base of NetBIOS networks, Microsoft developed NetBIOS over TCP/IP (NetBT), dropped the NetBEUI protocol.
• NetBT allowed Windows systems to use both NetBIOS names for local tasks and DNS names for internet tasks.
• Resource sharing, such as file and printer access, was handled by the Server Message Block (SMB) protocol, which initially used NetBIOS names but now operates independently over TCP port 445.

hosts

The ARPANET used a txt hosts file for name resolution, which stored IP addresses and corresponding system names on every computer in the network. The file was updated every morning at 2 a.m.

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Part of an old hosts file might look something like this:

140.247.21.53 HARVARD 128.2.0.1 CARNEGIE 23.54.122.103 AMES 129.55.0.1 MIT

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• Despite ARPANET's decline, the hosts file persists in modern systems, located in specific directories on Windows, macOS, and Linux.

DNS

The ARPANET team replaced the hosts file with the Domain Name System (DNS) to create a more scalable solution that could handle different cultures, time zones, and network sizes.

How DNS Works

DNS servers devides their work in two halves: resolvers and name servers (often just called DNS servers).

• Resolvers query name servers (DNS servers) to get a domain’s IP address
• Name servers hold domains and IPs in a database called zone.
• The top-dog DNS name server (The “root” of a global hierarchy) covers every name accessible on the public Internet.
• Just below the root in the global hierarchy is the top-level domain servers that handles TLD names, such as .com, .org, ….