Interesting case where Exchange is not installed on-premises

I’ve recently been working on projects as opposed to cases, and so I haven’t had anything too exciting to write about lately. However, I recently worked a case that I found quite interesting and wanted to share it here. I believe this is an edge case, but makes for an interesting problem none the less….

P2 Headers Now Respected for End User Safe and Blocked Senders Lists

Exchange Online Protection will now evaluate both the P1 and P2 headers in a message against an end users safe and blocked senders list. I know, I’m super excited too! Previously only the P1 header of a message was compared to these lists. Not only does this make blocking or safe listing within Outlook or…


The Resolver

While “The Resolver” would be a great nickname for a councillor, that’s not quite what we are talking about here. When processing inbound messages, Exchange Online (not EOP Stand Alone) will always resolve the recipient to the primary SMTP address before evaluating transport rules. Why does this matter? If you are writing transport rules that trigger…


Prevent DLs From Receiving ESNs

I’m often asked how to prevent an End user Spam Notification (abbreviated as ESN from this point on) from being sent to a distribution list (abbreviated as DL from this point on). Before getting to the answer, let’s start off with some background information on ESNs to see why this question comes up in the…