The Authentication Whitelist feature whitelists authenticated emails. This is useful if your users are allowed to relay emails through the ORF server using SMTP authentication from external IP addresses.
Disabling this test may prevent users (who successfully authenticate) from relaying emails, so it is highly recommended to keep this option in the default, enabled state.
Under Microsoft® Exchange® 2019/2016/2013/2010/2007, this option whitelists emails from senders that successfully authenticate as 'Partner' or 'Organization' and also from senders configured for Exchange anti-spam bypass.
Under IIS SMTP, the Authentication Whitelist test will whitelist emails from authenticated senders (SMTP authentication).
Enable or disable the Authentication Whitelist test by clicking the ON / OFF button on top of the page, or on the page.