# What is CLI (Calling Line Identification)?

> CLI (Calling Line Identification) is the telephone number presented to the called party as the origin of a call — the voice-network equivalent of an SMS sender ID. It is carried in call signaling (SS7 IAM, or SIP From / P-Asserted-Identity). CLI can be legitimately set — a business showing its main number — or fraudulently spoofed, which is exactly why authentication frameworks like STIR/SHAKEN exist. See /answers/what-is-ani, /answers/what-is-stir-shaken, and /answers/what-is-did.

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- Language: en
- Last reviewed: 2026-07-22
- Publisher: BroadNet (https://www.broadnet.me)

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