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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.
I am wondering if there are anyone from Exchange Online support team can verify this behavior ?
I opened support ticket with Fortinet and Microsoft, Fortinet support 's attitude is "not my problem, ask Microsoft"; The Microsoft support working on my case doesn't seem understand the issue so far.
Now I see other customers are having same problem:
https://www.reddit.com/r/fortinet/comments/un12cw/fortimail_recipient_verification_using_rcpt/
"I’ve come across an interesting issue that support from either side has been unable to solve so far"
This doesn't look promising.
The result is Fortimail will count any bogus email as a valid user account and consume a user license.
I opened support ticket with Fortinet and Microsoft, Fortinet support 's attitude is "not my problem, ask Microsoft"; The Microsoft support working on my case doesn't seem understand the issue so far.
Now I see other customers are having same problem:
https://www.reddit.com/r/fortinet/comments/un12cw/fortimail_recipient_verification_using_rcpt/
"I’ve come across an interesting issue that support from either side has been unable to solve so far"
This doesn't look promising.
The result is Fortimail will count any bogus email as a valid user account and consume a user license.
Arindam_Thokder might be able to help, if support gets you nowhere.