Why do several websites share one IP address?¶

One server or public-facing service can deliver many websites from the same IP address. The browser states which hostname it wants, and the receiving system selects the corresponding site.

How the server tells them apart¶

For ordinary web traffic, the requested hostname is carried in the HTTP request. For encrypted HTTPS traffic, the connection normally also indicates the intended hostname during setup so the service can choose the correct certificate and destination.

A useful analogy is a large office building with one street address. The company name on the envelope tells reception which tenant should receive it.

Shared hosting, website builders, reverse proxies and content-delivery networks all use this arrangement. Two domains resolving to the same address may therefore share nothing more than a provider. The match is usually weak unless the address belongs to a small or dedicated environment.

A technical link becomes more meaningful when combined with less common matches: the same customer account, nameservers, certificate details, analytics identifier, contact data, payment destination or administrative access.

The reverse is also true: websites under common control may use entirely different addresses and providers.