STEP 4 - Outbound Relay 'Smart Host'

Created by Jason Carreiro, Modified on Mon, 26 Feb 2024 at 03:47 PM by Yves Lacombe

Important: Before configuring the outbound mail flow through PP -- you need to add an entry to your client's SPF record. Usually most organisations already have one. The existing SPF record looks like this:

"v=spf1 ip4: ip4: -all"

The SPF record tells the world who is allowed to send mail on your or your client's behalf.

You need to add this entry to the SPF record:

US Stacks: 
EU Stacks:

So the SPF record becomes like this:

"v=spf1  ip4: ip4: -all"

This is covered in the "Getting started with proofpoint" guide.

What is and When to use a smart host?

A smart host is an email server through which other servers, if they are configured to use it, can send their outbound mail through instead of sending it directly from their IP address. Note also that the smart host server can hide your mail server’s IP address from the public.

So why do we use it?

Most of the reason that we need to use a Smart Host is to prevent the mail server Ip address from having a bad reputation and mail would be blocked by most mail servers.

Configuring Smart host:

Step 1

  • Follow these steps to enable relaying on modusCloud.

          1- Log into the modusCloud website US or EU

          2- Click the Features tab.

          3- Enable Outbound Relaying and click Save.

          4- Click on the Domains tab.

          5- Click on the button Manage Hosted Services or New sending servers (if you are using                           Exchange on premise)

          6- Click on the slider of Office 365 or enter your exchange IP address (if you chose New sending                      servers in STEP 5)

         7-  click Save.

Note: When this (Manage hosted services) is enabled modusCloud will automatically manage the IP ranges of Office 365 published by Microsoft. Updates are performed daily.         

In this Document we will focus on exchange 2016 to create a smart host.

Step 2

        . open the ‘Exchange Administration Center’ EAC

Step 3

        . Login to the EAC as administrator

Step 4

        . in the left menu select ‘Mail Flow’

        . Select ‘Send connectors’

        . Click ‘New’ to add a new connector

Step 5


        . Enter a name of your choice, i.e.  AuthSmtp

        . Select ‘Internet (For example, to send internet mail)

        . click Next

Step 6

        . Click ‘Route mail through smart hosts’

        . Click ‘Add’ to add the new server that will act as a smart host

        . Click ‘Next’

Step 7

        . Enter the Smart Host IP address

        . Click ‘Save’

Note: if you are  hosted in

. EU make sure to use 

. US make sure to use  

Step 8

        . Notice the info you entered in the smart host window

Step 9

. Click ‘None’ if no Authentication is required otherwise ‘Basic authentication’  (screen shot below)

        . Do nothing for ‘Exchange server authentication’

        . Do nothing for ‘Externally secured (for example, with IPSec)

Step 10      

        . click ‘Add’ to all the hosts that are allowed to send through this connector

Step 11

        . Select Type ‘SMTP’

        . Enter ‘*’ in the FQSN field

        . Enter 1 in the ‘Cost’ field

        . Click ‘Save’

Step 12

        . Click ‘Add’ and enter permitted source server

        . Click ‘Finish’

Step 13

        . Click the appropriate server from the list

        . Click ‘Add’

        . Click ‘OK’

        . the Click ‘Finish’

Step 14

. Display of the sent connector just create that will be used to send outbound mail.