Resolved DKIM issue - Route email from Exchange via Plesk VPS

[George Thalassinos]

Hi, I have a Linux VPS which serves 20 some domains and Plesk Onyx to manage it. I have set up DKIM on my VPS which works ok for all but one, which uses an SBS2011 server with Exchange 2010.

They have a problem because Exchange sends emails directly via a smarthost and the IPs of the receiving mail server (on the VPS) and that of the sending mail server (SBS2011) are different. Therefore DKIM fails.

I need to route their emails via my VPS so that they appear as being sent from the DKIM verifiable server.

At the moment I have set up my Plesk as such :
Plesk Onyx 17.8.11
Installed Mail Server : Postfix
Outgoing Mail Mode : Send from Domain IP addresses
Relaying : Authorization Required / SMTP
DKIM : Allow signing outgoing mail

Exchange last attempt was to create a Send Connector as such (without success) :
FQDN this connector will provide in response to HELO or EHLO : remote.domain.gr (resolves to the Exchange static public IP)
Address space : SMTP * 1
Route Mail through the following Smart Hosts : [VPS Public IP]
Basic Authentication : Username = info@domain.gr (TLS not checked), Password = the corresponding Password (verified), Exchange Server Authentication = No, Externally Secured = No

Any ideas as to how to tackle this?
Thanks in advance

 

[George Thalassinos]

Actually, the options I included in my question were the ones I tried out last night, so they were not "without success" at the time of writing.

I had tried other options without success the previous days, but this morning I received an email reply from the users of the relevant domain that their emails were being delivered correctly.

Now, if the DKIM reports come back as PASS, the issue will have been resolved. I will post back when they come in.

 

[George Thalassinos]

The above settings work. The reports show <dkim>pass</dkim> and <spf>pass</spf>.

Therefore case is closed.