How to host many domains on one IP?
Company: Google
Role: Software Engineer
Category: System Design
Difficulty: medium
Interview Round: Technical Screen
You have a single Linux server with **one public IPv4 address**. A coffee shop, butcher shop, and auto repair shop each want their own website and **their own domain/URL** (e.g., `coffee.example`, `butcher.example`, `auto.example`).
How would you host all of these sites on that one server/IP?
Cover:
- DNS setup
- How incoming HTTP/HTTPS requests get routed to the correct site
- How you would handle TLS certificates
- Key operational/security considerations (isolation, logging, deployments)
Quick Answer: Evaluates knowledge of DNS, HTTP/HTTPS request routing, TLS certificate management, and operational/security trade-offs when hosting multiple domains on a single public IP. Commonly asked to probe architectural reasoning and practical deployment trade-offs in the System Design domain at an architectural/operational level of abstraction.