SPF "breaks" email forwarding. SRS is a way to fix it.
This is true on one of the cPanel/WHM servers I manage. A customer has a forwarder set up and she is complaining that emails sent to that email address
@herdomain.com bounce. Investigating the logs, I see that my server tries to forward the emails as she has requested, and her other provider is rejecting the email because my server isn't allowed by SPF. Since we have no idea who will be sending her email, it's not feasible to have me in the SPF record for all her senders' domains, clearly.
It seems like SRS: Sender Rewriting Scheme is the way to go. is there any official support for SRS from cPanel? If not, can it be added manually via the command line / Exm Configuration Editor?