Accepted Domains, Safe Senders List and You

@UWEmailSys, if you install the anti spam agents on the hub(s) that is receiving mail from your app servers and then put those servers on the IP allow list you will not have to disable outlook's anti-spam checks.

We do NOT advise turning off outlook's AS checks.

@Nivritti, I understand that setting up all your app servers to auth is not practical that is why I proposed installing the anti-spam agents on the hub(s) your app are relaying off of and putting those IPs on the allow list.

Ultimately while it may seem expedient to put your entire accepted domain on a safe list from a security standpoint this would be not be a good idea particularly with how spoofing one’s domain is such a prevalent tactic for spammers out there.  Using the IP allow lists or pushing out safe lists to outlook via a GPO are two good ways to handle these situations where on the one hand you'd like you app relays to send from different local addresses AND want your user's inboxes free from spam.

Thanks