As marketers, you know that the race to achieve inbox placement is
getting tougher every day. The best way to land your emails in your
contact's inbox is by implementing email authentication techniques. At
Zoho Marketing Automation, we urge our users to implement SPF, DKIM, and DMARC. For
your emails to pass the DMARC validation, you must implement SPF and
DKIM. When your emails pass the SPF and DKIM alignment and validations,
your emails will pass the DMARC validations performed by mailbox
providers.
Let's dive deep and learn about achieving SPF alignment by using a custom return path address.
What is a return-path address?
The
return-path address is an envelope address used by email senders to
receive notifications about email bounces. Email senders can analyze the
bounce receipts and take necessary corrective measures. It's important
to understand that an email can only have one return-path address. You
can find the return-path address in the email header.
In Zoho Mail, you click on an email, navigate to the top-right arrow, and click on Show original. The message header details will open in a new window.


Here are
instructions to get the email header of other commonly used mailbox providers.
What is a custom return path address?
Here,
the domain of the sender address and the return-path address do not
match. In this situation, the SPF alignment will fail.
A
custom return-path address will use the domain that is used by the
sender address. For example, if your sender domain is zylker.com, you
can create a custom return-path address like
bounces@bounce.zylker.com.
When the domain of your sender address and that of your return-path
address match, you can achieve SPF alignment and your emails will pass
the SPF validation.
How to set up a custom return-path address
Login to your Zoho Marketing Automation account.
Click Settings (Gear-shaped icon) at the top right corner.
Under the Marketing Channels section, click Email.
Click Senders and Authentication tab at top.
Click Setup against the domain for which you need to set up a custom return-path.
In the slide-in window that appears, type your host name (sub-domain name) – which you've used in your domain's DNS – in the Specify the Host Name field.
Next, copy the CNAME record and paste it in your domain's DNS. Publish the CNAME record in your domain's DNS.
After the record is published, come back to this page in your Zoho Marketing Automation account and click Authenticate.

Now, your domain will move from Incomplete to Authenticated status.
Notes:
The CNAME will be unique for each Zoho Marketing Automation organization.
You can set up the custom return-path only after you've authenticated your domain by publishing the SPF and DKIM records in your domain's DNS. Learn more about authenticating your domain here. It isn't possible to set up the custom return-path first and authenticating your domain after that.
If there are any issues with the CNAME record or if it gets deleted at your domain's DNS, the domain will move back to Incomplete status and the custom return-path should be set up again.
Advantages of using a custom return-path address
Having
a custom return path address will help your emails pass the SPF
alignment in DMARC validation. When you implement SPF, DKIM, and DMARC,
it will improve email deliverability and prevent your emails from
spoofing attacks.