I have an email account [email protected] with mail.live.com .
I also have a Gmail account. I have set up the 'Send mail as' feature in Gmail to send mail as [email protected], and this works correctly.
My question is, if I send an email from Gmail 'as' [email protected], how does the recipient's server verify that Gmail was authorized to send mail for example.com?
I have some knowledge of SPF records, and I know that the SPF record for example.com says that only messages originating from hotmail.com servers are valid.
The message that Gmail sends out has the @gmail.com address in the Return-Path and Sender fields, and so the SPF check is done against gmail.com and not example.com.
I have tested this with the test service at verifier.port25.com and it passes.
SPF check: pass
DomainKeys check: neutral
DKIM check: pass
Sender-ID check: pass
SpamAssassin check: ham
It would check the SPF record, which would indicate a failure and thus a higher spamminess score. If you're going to be sending from Gmail, you should have Gmail in the SPF.