How DNS works

Computer Networking
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DNS is a fundamental part of how the internet works, and understanding its intricacies is important to stay ahead of the curve in the IT world.

:mag: Think of DNS as the internet’s phonebook. :books:

It’s the hero that turns friendly domain names (like \www.mypage.com) into IP addresses that computers use to chat! :computer::left_speech_bubble:

:one: You type a URL into your browser.

:desktop_computer: Your computer first checks its local resources. This includes:

  • :page_facing_up: The host file - a simple text file mapping domain names to IP addresses.

  • :package: Various caches - mini storage areas in your computer, operating system, and router where recently visited website addresses are stored.

This quick check lets your computer find the IP address of a website without needing to ask a DNS server. :rocket:

:two: If the domain name isn’t in the host file or any of the caches, your computer sends a request :love_letter: to a DNS server.

The server searches its database and returns the correct IP address to your computer. :dart:

:three: Once your computer gets the IP address from the DNS server, it uses that address to connect to the website. :globe_with_meridians:

It also stores the domain name and IP address in its DNS cache for quick access the next time you visit the website. :arrows_counterclockwise:

:deciduous_tree: DNS is a hierarchical system, with DNS servers arranged in a tree-like structure. :evergreen_tree:

This structure, known as the DNS namespace, allows for efficient and quick resolution of domain names to IP addresses, ensuring the smooth functioning of the internet. :rocket:

:cloud: Now, let’s consider how DNS operates in today’s expansive Hybrid Multi-Cloud environments. Public Clouds resolve their Internal FQDNs to Service Endpoints using:

  • :hammer_and_wrench: The Provider’s own DNS Resolvers,

  • :label: C-Name aliases in Private DNS Zones,

  • :link: And Virtual Network Links.

To resolve these FQDNs from another Cloud (Private or Public), it requires Conditional Forwarding and additional Routing between the EDGEs with NAT/SNAT. :bridge_at_night:

While SNAT/NAT might not always be necessary, it’s good to have for ensuring seamless interconnectivity. :globe_with_meridians:

:framed_picture: The attached gif simplifies the DNS process, but remember, in today’s multi-cloud environment, the process is much more complex and fascinating! :cloud_with_lightning:

How DNS works

LinkedIn (and Credits): :point_down: