IP restriction is an access control that allows or blocks requests based on the source network address. In practice, an organization may only trust connections from a corporate VPN, office ranges, or other allowlisted IPs. It is useful for reducing exposure, but it is not the same as true identity verification: if a request reaches the service through a different application path, or through a feature that is not checked by the same filter, the restriction may not apply.
In cyber security, that gap matters because attackers often look for alternate entry points that bypass perimeter rules. A web login, an API call, an email-driven workflow, or a trusted integration may be governed by different controls. Defenders should treat IP restriction as one layer, not a complete boundary, and pair it with strong authentication, least privilege, branch or action approval, and logging. If a service advertises IP filtering, verify exactly which endpoints and workflows it covers.