Kelli GrayAffects v122+
"As a system administrator, I would like to see cPanel add the Authenticated Received Chain signature (ARC-Sign) to forwarded mail, so that there is better deliverability to users who have providers that check that header (including Gmail)."
Supporting ARC maintains email deliverability by enhancing email security and authentication, preserving authentication results as emails pass through intermediaries like mailing lists or forwarding services. It helps prevent spoofing, phishing, and email delivery issues, leading to increased trustworthiness and better email deliverability for senders.
To use this setting, go to Exim Configuration Manager Basic Editor and enable "Enable ARC signing for outgoing mail" setting.
Kelli GrayThis feature is being released as Experimental because we cannot guarantee outbound mail will not be marked as spam by other providers. We believe mail deliverability is improved by this feature, such as when DKIM and SPF checks fail, or when the receiving provider requires ARC. However the problem cannot fully be resolved because there is no publicly available single source of truth for trusted mail providers (yet).
Kelli GrayFor clarification, this project is to add ARC signing to outbound mail only.