TABLE OF CONTENTS

• Introduction
  • Whitelisting References
  • DNS/Cname Setup
  • Setting up a Verified Domain
  • Single Sender Emails

Introduction

Thomalex System uses SMTP2go as an email partner. 

This page covers all neccesery references needed for the client's email domain to be verified or whitelisted.

Whitelisting References

In order to list IP addresses with your incoming (MX) server please take a look at the following lines.

SMTP2GO sends out emails from a range of different IP addresses. The current IP addresses we use can always be found by looking at the SPF record for spf.smtp2go.com: https://mxtoolbox.com/SuperTool.aspx?action=txt%3aspf.smtp2go.com

On the above page, you will see a series of IP address ranges, in the following format:

ip4:xyz.xyz.xyz.xyz/nn (this is called CIDR format)

If it is possible, it is often a good idea to have your incoming (MX) mail server whitelist the IP ranges shown on the above page. 

If your account has one or more dedicated IP addresses, you will only need to whitelist your account's dedicated IP addresses.

The benefits of whitelisting with your incoming mail server include:

- Automatically bypassing unnecessary spam filters (as you have sent the emails, they shouldn't need to be scanned).

- Automatically bypassing any blocklist checks (just in case any IP address ever features on a blocklist).

DNS/Cname Setup

If you want to send an email using your own "from" email address, you need to add a few additional settings in your DNS provider which will confirm that smtp2go can send an email on your behalf.

This is needed in order to prevent emails from going to the spam/junk folder and being rejected.

These are the records that need to be added:

Setting up a Verified Domain

For maximum email delivery rates and better branding, we recommend adding any domain names by the Thomalex team (that you send emails from) to the Verified Senders section. 

Adding a verified sender domain means that SPF and DKIM are automatically handled by SMTP2go, and use DNS records at your own domain name.

Image no.1 Correctly Verified Domain Example

Single Sender Emails

If you're unable to add/edit the DNS of your domain name, you can choose to add individual email addresses to the "Sending > Verified Senders > Single sender emails" page. You'll be sent an email containing a confirmation link which you'll need to click to activate the email address as a verified sender.

You can optionally choose to add a custom message to the invitation email, which may help the recipient understand that your business/app is sending the email (as the invitation email otherwise just contains SMTP2GO branding).

On a technical note, emails sent using a single sender email don't use the sender email's domain for DKIM or SPF, so emails will show as being sent 'via smtpcorp.com' (or another of our domains) in Gmail. We recommend adding a sender domain instead of a single sender email if you're able to edit the DNS of your domain.