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Networking Fundamentals · Foundational

Localhost

The hostname that resolves to the local machine's loopback address, 127.0.0.1 or ::1.

Definition

Localhost is defined in the hosts file on most systems and is reserved by RFC 6761 so that it should always resolve to loopback. Developers use it to reach services running on their own computer.

Example

Browsing to http://localhost:8080 reaches a web server running locally on port 8080.

Exam tip

localhost is a name; 127.0.0.1 is the address it maps to.

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