We have linked the domain of our company to Google Apps and we also have a Kerio Connect (mail server) installed in our company which uses Google as SMTP relay. As google requires SMTP authentication we use one of our mail addresses for authentication. But it causes google to substitute "From" header with the address of the user used for authentication.
For example, we want to send email from firstname.lastname@example.org. User email@example.com is used for SMTP authentication in SMTP Relay settings of Kerio Connect mail server. The mail gets delivered, but on recipient side it says that the message is from firstname.lastname@example.org, though it was actually sent from email@example.com (Reply-to header is also set to firstname.lastname@example.org :( ).
In the "Sending mail from a different address" section of Gmail help there is an explanation of how I can send email from, say, email@example.com when firstname.lastname@example.org is used for authentication. - They say I need to sign up to Gmail with user2@ and add user1@ as another mail address I own (Mail settings -> Accounts -> "Send mail as" section). And it works. For example, when I sign up with email@example.com and add firstname.lastname@example.org as another mail address I own, then I can send email from email@example.com using firstname.lastname@example.org for authentication, and the recipient will see that the message is sent from email@example.com.
But what if I have a hundred of email addresses on the domain? I don't want to add those 100 addresses in the settings.
I just want that any user (*@company.org) could send email using firstname.lastname@example.org user for authentication and I want recipient to see that the message is sent from *@company.org, not email@example.com.
Is there an easy way to do that?