Your Guide to Email Authentication with Sendloop

Best Practices in Email Marketing 2019

Table of Contents

What is email authentication?

⚠️ DNS Records

Setting up email authentication requires you to work with DNS records, but don’t worry if you’ve never done so. This article will cover in detail all of the steps you need to perform.

Email authentication is a way to prove that your email isn’t a forgery. More specifically, it involves granting permissions to Sendloop to send email on behalf of your domain (for example, if your site’s URL were, your domain is With authentication, email providers know that the incoming email is valid and isn’t a disguise for spam (doing this is a process known as phishing).

Because spam is so prevalent, Internet service providers (ISPs) and other email servers are using authentication to control the inflow. As such, it’s important that you take steps to authenticate your emails.

⚠️ Heads Up!

Without email authentication, you’ll see a poor inbox delivery rate.

Types of Email Authentication

Sendloop supports use of two types of email authentication:

  • Sender Policy Framework (SPF): When you use SPF, you provide a list of IP addresses that you use to send emails. Email providers, upon receiving your emails, look at the IP address that sent the emails and compare it to your list. If there is a match, it delivers the email. If not, it flags it as spam.
  • DomainKeys Identified Mail (DKIM): When you use DKIM, there are two “keys” that correspond to your site. One is public, and it can be seen by anyone. The other is private, and only your website’s servers know what it is. When you send an email, your email server embeds your private key in your email so that receiving email providers can compare the two keys to make sure that the message is from who it claims to be and that it hasn’t been tampered with during sending.

How do I set up email authentication?

To set up email authentication, you’ll need to implement two changes to your DNS records. Sendloop’s email authorization wizard can help you identify the changes you need to make.

Using the Email Authorization Wizard

After logging in to your Sendloop account, click Settings in the top navigation bar.

On the Settings page, click Sender Domain Authentication. If this is the first time you’ve done this, you’ll see the Authenticated Sender Domains* page. Click on Authenticate Sender Domain to proceed.

When prompted, provide your domain. Click Add Domain to proceed.

Once you’ve provided Sendloop with your domain, you’ll be redirected to the Domain Control Panel. This page shows you which records you need to update/add.

⚠️ Need help?

If you need help modifying your DNS records, reach out to your network administrator. If you do not have one, contact your web hosting service for assistance. You can click on the Send setup instructions to your server admin link to provide them with the information relevant to your Sendloop account.

Set Up the SPF Record

To add an SPF record for your domain, you’ll need to create one using any plain text editor, such as Notepad. The only text you’ll need to include in the file is the value provided on your Domain Control Panel, which looks like this:

v=spf1 a mx ~all

⚠️ Update an existing SPF record

If you already have an SPF record for your domain, simply add in between v=spf1 and ~all.

Set Up the DKIM Record

To add a DKIM record for your domain, you’ll need to create one called sl._domainkey using a plain text editor (such as Notepad).

Within the sl._domainkey file, include the DKIM signature provided in the Value column of the row indicating that you’re missing a DKIM record. The signature looks something like this:

v=DKIM1; k=rsa; p=MIGfMA0GCSqGSIb3DQEBAQUAA4GNADCBiQKBgQC8A2AmheQxbskyETU6wx/ FQHZDo4E9/UlTzmqW/BRcdN73WhSL5mAQ/hyyk9hbSPVbgdwm8VFl1GYfoMildmEe4p J45MHSc4PUWpzcevr2+5g9YoxzGvuJp8NjwScvFRz4gSsVu5SYo0sJdO2xvO+TKaZTtH 0D+Z6driUc3vQuWQIDAQAB;

OPTIONAL: Set Up the CNAME Record

While this step is optional, we recommend adding a CNAME record. This allows you to alias the links used in your email message. For example, if you use, you might add as a pointed to Doing so results in consistency that boosts your inbox delivery rate.

To add a CNAME record, create a file using a plain text editor (such as Notepad), that contains the value displayed in the Domain Control Panel. It will look something like this:

Check Your Authentication Set Up

Once you have implemented the appropriate DNS record changes, you can click Check DNS Records on the Domain Control Panel to test your changes. Sendloop will verify your DNS records, and if everything works, the red warning flags will disappear.

⚠️ DNS changes may take several hours to propagate, so if you don’t see an immediate change, try again at a later time.