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My son just started a new job and sent us emails with his new company email.

We use m365 for our mail and have the 'standard' spam filter enabled.

His email wound up in spam.

Looking in the header, I see 

a) that they are sending from m365

b) a fail, noted below.  

Googling, i found pages about ARC being enabled for m365 now and that this causes problems sending to other m365 users. 

Can anyone help me understand what the sender didn't do related to email?  

a) so I know to avoid it for my clients

b) he can mention it to their people so it can get fixed?

ARC-Authentication-Results: i=2; mx.microsoft.com 1; spf=pass (sender ip is
40.107.244.79) smtp.rcpttodomain=mydomain.com smtp.mailfrom=ourdomain.bank;
dmarc=bestguesspass action=none header.from=ourdomain.bank; dkim=pass (signature
was verified) header.d=ourdomain1.onmicrosoft.com; arc=fail (47)

THANKS!


Spicy Joseph
Jalapeno
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Spicy Joseph This person is a Verified Professional
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You might find this useful:

https://postmarkapp.com/blog/what-is-arc-or-authenticated-received-chain

2 Replies

· · ·
Spicy Joseph
Jalapeno
OP
Best Answer
Spicy Joseph This person is a Verified Professional
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You might find this useful:

https://postmarkapp.com/blog/what-is-arc-or-authenticated-received-chain

1
· · ·
LookingToAlwaysLearn
Serrano
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Spicy Joseph

Thanks, but that doesn't tell me how to set it up / change it.

I did find this page that seems to deal with the specific issue i saw in this email - the header.d is using onmicrosoft.com

https://www.reddit.com/r/Office365/comments/7zqtpr/sent_mail_headers_show_original_tenantdomain_name...

1
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