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 [email protected]. User [email protected] 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 [email protected], though it was actually sent from [email protected] (Reply-to header is also set to [email protected] :( ).

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 protected] when [email protected] 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 protected] and add [email protected] as another mail address I own, then I can send email from [email protected] using [email protected] for authentication, and the recipient will see that the message is sent from [email protected].

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 [email protected] user for authentication and I want recipient to see that the message is sent from *@company.org, not [email protected].

Is there an easy way to do that?

  • 1
    why do you need to use gmail as your relay?
    – gravyface
    Oct 18, 2011 at 0:45
  • gravyface, well, I can't use local mail server (Kerio Connect) because many other mail server's will not accept my emails because will not count my local smtp server as trusted. And I can't use my domain hosting's (Hostgator, for example) smtp relay, because now my domain MX record points to google. So, as I understand, I have to use either gmail, or another commercial smtp relay.
    – nightcoder
    Oct 18, 2011 at 1:00
  • Why not just configure your clients to send directly to google, instead of through your relay? I don't see why you think you need your local Kerio server anymore at all. Oct 18, 2011 at 3:31
  • I would just setup SPF records and make sure you have reverse DNS setup at your office and you should be good to go to send out mail directly. Either that, or have the clients send directly out via Google in their Outlook/mail client's SMTP settings as JedDaniels suggested.
    – gravyface
    Oct 18, 2011 at 11:58

4 Answers 4



they do provide what you want if you look

  • Take note of the note on that page: "Note: SMTP relay service is not available with the legacy free edition of Google Apps." Jun 12, 2015 at 12:11

I've looked into the same situation and you cannot use Google Apps as an outbound relay the way you want.

The situation may be different if you sign up for Postini, I haven't really looking into that service.

Changing your MX records to send INCOMMING mail to Google Apps, doesn't have any effect on your OUTGOING mail. You can send it from any server you want, ie use your host or your ISP.

A few things to be careful of: 1) Make sure your SMTP server has a reverse lookup entry. 2) Make sure your SMTP server name resolves the the same address as the server, ie if EHLO is SMTP.yourdomain.com.au, then an nslookup for SMTP.yourdomain.com.au needs to match the address. 3) If you're using SPF, make sure you include your non-Google SMTP servers in the TXT record (as well as the Google settings). 4) Ditto if you're using DKIM.

1 & 2 will make sure you don't get flagged as spam straight away.

  • Postini will do act as a relay as the OP wanted and will not change the "from" header.
    – MikeAWood
    Oct 18, 2011 at 6:52
  • Sadly, Postini is on the way out the door. By the end of 2013 it will no longer exist. Oct 24, 2012 at 21:39

Ask Google. And as they provide you a way to get this accomplished you should follow their guide. If you don't like the way they do then you have to complain to them. Or change the provider.


thank you for your replies.
Although the method I described in the question works (though it's far not perfect) we have decided not to use Gmail as SMTP relay for now. For now we are using our hosting server's SMTP.

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