I've been trying to implement Microsoft's advice on disabling Direct Send, as we've been seeing messages that can't be properly filtered because they use this method. We applied the commands suggested in a Microsoft Community Hub article to manage this, but we're having issues specifically with Paubox. Although we use their API to send emails, any email that comes to our addresses from them is being routed directly through our tenant, leading to blocks because Direct Send is set to rejected mode. Has anyone dealt with this before and can offer some guidance? All of our DNS records are configured to route messages correctly, but we can't seem to resolve this issue.
5 Answers
It sounds like you need an inbound connector too. If you can configure it to trust those specific IPs, it might solve your issues. Right now, since their SPF and DKIM records are in your DNS, their emails are likely being treated as external because Direct Send is blocking them.
Have you considered creating an inbound connector for Paubox? It could help if you scope it to their IPs and mark it as trusted. This way, their emails would be treated as internal, allowing you to disable Direct Send without problems.
You could also explore allowing Direct Send but securing it with an inbound connector using either IP or certificate for extra safety.
Just a side note, it would be easier if you had linked the original Microsoft tech community article directly instead of using a Google Share link. Here's the link: https://techcommunity.microsoft.com/blog/exchange/introducing-more-control-over-direct-send-in-exchange-online/4408790.
Have you tried contacting Paubox support about this? It seems strange that you’re facing this issue after disabling Direct Send, as others have likely run into problems with this.
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