We currently use Proofpoint for inbound mail filtering in front of our email server hosted on latest SmartMail. We recently turned on Proofpoint outbound filtering and changed SmarterMail to use ProofPoint as a gateway which worked great. The issue is that we have some users how have forwards setup to external emails. This is broken once we turn on outbound via Proofpoint because Proofpoint sees those messages as coming from the ORIGINALsender and not our users, hence it gives them a relay not allowed rejection. I have had a couple of cases open with SmarterTools and have tried a couple of setting changes (most notably SRS rewrite) but it still fails with the same error.
I now have some users who REALLY need to be able to forward to external email addresses and so my only recourse is to turn off the ProofPoint gateway for the entire domain to make this work for a handful of users. So I would like to request a feature allowing us to turn on/off the gateway no only by Domain, but also by User.
Has anyone else run into this and if so, were you able to get around this limitation?