Continuously Enforce IP Addresses in Login IP Ranges

The Enforce login IP ranges on every request Session Settings option restricts the IP addresses from which users can access Salesforce to only the IP addresses defined in Login IP Ranges. This option affects all user profiles that have login IP restrictions.
Available in: All editions

User Permissions Needed
To set session security: “Customize Application”
  1. From Setup, click Security Controls | Session Settings.
  2. Select Enforce login IP ranges on every request.

    This option enforces the IP addresses in Login IP Ranges for all Salesforce access requests, including logins from client applications. If this option is not selected, login IP ranges are enforced only when users log in.