Utilizing different virtual-mtas with a single delivery server

Utilizing different virtual-mtas with a single delivery server

Utilizing different virtual-mtas with a single delivery server

This article requires Octeth v5.0.0+ and PowerMTA v4+ versions.

Our Purpose


If you are using PowerMTA with more than one IP addresses, you may be interested in setting up separate virtual-mta directives for each IP address you have. And then you may want to utilize these virtual-mtas for different users or recipients (using global segments feature). In such a case, this article will guide you to setup and utilize your IP addresses using;

  • PowerMTA’s virtual-mta, smtp-user , and smtp-source directives
  • Octeth’s delivery server, and custom email headers features

PowerMTA Configuration

This article assumes that you have basic understanding and knowledge of PowerMTA configuration. For any questions regarding PowerMTA, please don’t hesitate to contact us.

Let’s say you have, and IP addresses that needs to be utilized on your email marketing campaigns. We will setup separate virtual-mta directives for each one of these IP addresses:

        smtp-source-host my-sender-domain-1.com

        smtp-source-host my-sender-domain-2.com

        smtp-source-host my-sender-domain-3.com

The next step is to setup an SMTP user and SMTP source directive to utilize these virtual MTA’s:

<smtp-user my-smtp-user>
	password "gKeS9P9A206U"
	source {my-smtp-source}

<source {my-smtp-user}>
	always-allow-relaying yes
	allow-auth true
	require-auth true
	process-x-virtual-mta yes

That’s it. We have setup separate virtual MTA for each IP address we have and then defined an SMTP user account to utilize those virtual MTA’s. You can definitely expand the functionality of these virtual MTA’s, SMTP user and source directives but these parameters are must have configurations.

As the last step, reload your new PowerMTA configuration:

$ pmta reload

Octeth Configuration

On your Octeth administrator dashboard, go to [Settings → Delivery Servers] section and create a delivery server:

Creating Delivery Servers


Create a separate delivery server with the same credentials for each IP address you have.

Creating Custom Email Headers

Head over [Admin Area → Settings → Email Delivery → Custom Headers] section and create a separate email header for each deliery server:


This setting will make sure that when any of your delivery server is utilized on the user group or global segment level, that specific x-virtual-mta header will be added to your outgoing emails and this will cause PowerMTA to reroute your outgoing emails through a specific virtual MTA.

Delivery servers can be utilized on user group level. To assign a delivery server to a specific user group, go to user group management area and make the assignment. Click here to learn more about User Management.

On the other hand, you can also utilize a specific delivery server for a group of recipients based on their attributes and/or activities. Click here to learn more about Global Segments.


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