How a human-readable name like google.com turns into a machine-routable IP address.
Anatomy of a domain name
Take mail.google.com:
| Part | Example | Role |
|---|---|---|
| Sub-domain | mail | A specific service within the domain |
| Second-level domain (SLD) | google | The registered organization name |
| Top-level domain (TLD) | com | The broad category/registry (.com, .org, .io) |
The TLD-specific name servers are managed under root authority by ICANN (Internet Corporation for Assigned Names and Numbers) — note that domains are technically rented (registered for a renewable period), never permanently "bought."
The resolution chain — root → TLD → domain
Root DNS Servers → .io / .org / .com (TLD servers) → student.io / commonsense.org / google.com (SLD)
The root DNS servers are the first point of contact in global DNS resolution — they don't know the final IP, but they know which TLD server to point to next, which in turn points to the specific domain's name servers.
Full step-by-step lookup, typing google.com
Your computer first checks its own local cache — if you've visited recently, the IP may already be saved locally.
If not cached, the request goes to your ISP's local DNS server — the first external point of contact.
If the local DNS server doesn't have it cached either, it queries a root server.
The root server doesn't know the IP, but acknowledges and redirects to the correct TLD server (e.g. the .com server).
The TLD server returns the IP address of
google.com's actual name server.Your computer finally connects directly to
google.com's server using the resolved IP.