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Weird behavior of Exchange Online for none-existing email address
I am see a weird behavior of Exchange Online for none-existing email address, wondering if anyone can explain it. I am setting up a Fortimail Cloud service ( third party email protection service ...
- Jack_Chen1780 - This behavior is expected. The DBEB functionality can reject on either RCPT TO or on "End Of Data". The latter happens when the sending IP is shared between multiple tenants, and in order for EOP to correctly attribute to the recipient tenant, we need to traverse the headers which are available only after EoD.
BTW, EOP doesn't allow Dev tenants to setup incoming connector now: https://techcommunity.microsoft.com/t5/exchange/exchange-online-connector-creation-failed/m-p/3624401
Can someone reason with Microsoft we need to test stuff in dev tenant 😞
Arindam_Thokder
Microsoft
MicrosoftJack_Chen1780 - Dev tenants were used to relay phish emails through EXO using Inbound connector. Because of this misuse, we had to other way but to restrict that.