R
Robbin_003
Guest
So here's the problem. I work on an invoicing software package that sends mails in name of their customers. Customers need to set up their DNS to include a NS record, which delegates a subdomain to us. This allows us to control SPF/DKIM keys, so our customers don't need to be too techsavvy to get this going. Furthermore it allows us to send mails with correct keys in name of our customers, so the mails do not come in spamboxes.
So a large overview of the flow would be:
"Customer Domain" <---- Subdomain delegated to ----> "Invoicing Mailing Software" <---- Sending mail to ----> "Customer of our customer with 'from:' set to our customer's domain"
This works great; thousands of mails are send in name of our customer from our mailing provider. There is a problem however when a customer of our customer is using Outlook 2016: the subdomain is shown, instead of the customer domain as the 'from'. It seems that Outlook 2016 is using the wrong header to determine it's from field, namely the 'sender' email header, instead of the 'from' email header. Surprisingly enough, the webclient of Outlook is NOT affected by this and correctly shows the value of the from header in the from field in the interface, instead of the sender header in the from field, what the Desktop client is doing.
The headers that are send with the mail are as following (changed the domains for privacy reasons):
From: "Testdomain" info at testdomain dot com
Reply-To: "Testdomain" info at testdomain dot come
Return-Path: info at 123847thgashfjhjykf-invoicingcompany dot testdomain dot com
Sender: info at 123847thgashfjhjykf-invoicingcompany dot testdomain dot com
TL;DR:
Outlook is showing "info at 123847thgashfjhjykf-invoicingcompany dot testdomain dot com" in the from field, instead of "info at testdomain dot com".
We contacted Microsoft through phone and mail previously, and they seem to insist on changing our SMTP servers, but that is not the problem, since we can replicate this issue, by just importing an EML with these headers and the problem persists. It does not matter which mailprovider the receiver is using, it happens on all of them; POP3/IMAP/Exchange, it all doesn't matter. That's why we highly suspect that Outlook 2016 has a bug in which header it should use for the from field.
Maybe other outlook versions are affected as well, but that is not known at the moment.
Please help so that the correct domain is shown in Outlook 2016.
Continue reading...
So a large overview of the flow would be:
"Customer Domain" <---- Subdomain delegated to ----> "Invoicing Mailing Software" <---- Sending mail to ----> "Customer of our customer with 'from:' set to our customer's domain"
This works great; thousands of mails are send in name of our customer from our mailing provider. There is a problem however when a customer of our customer is using Outlook 2016: the subdomain is shown, instead of the customer domain as the 'from'. It seems that Outlook 2016 is using the wrong header to determine it's from field, namely the 'sender' email header, instead of the 'from' email header. Surprisingly enough, the webclient of Outlook is NOT affected by this and correctly shows the value of the from header in the from field in the interface, instead of the sender header in the from field, what the Desktop client is doing.
The headers that are send with the mail are as following (changed the domains for privacy reasons):
From: "Testdomain" info at testdomain dot com
Reply-To: "Testdomain" info at testdomain dot come
Return-Path: info at 123847thgashfjhjykf-invoicingcompany dot testdomain dot com
Sender: info at 123847thgashfjhjykf-invoicingcompany dot testdomain dot com
TL;DR:
Outlook is showing "info at 123847thgashfjhjykf-invoicingcompany dot testdomain dot com" in the from field, instead of "info at testdomain dot com".
We contacted Microsoft through phone and mail previously, and they seem to insist on changing our SMTP servers, but that is not the problem, since we can replicate this issue, by just importing an EML with these headers and the problem persists. It does not matter which mailprovider the receiver is using, it happens on all of them; POP3/IMAP/Exchange, it all doesn't matter. That's why we highly suspect that Outlook 2016 has a bug in which header it should use for the from field.
Maybe other outlook versions are affected as well, but that is not known at the moment.
Please help so that the correct domain is shown in Outlook 2016.
Continue reading...