Send authenticated email from a subdomain

Trying to improve your deliverability and send emails from a subdomain? Verifying SPF and DKIM can quickly turn into a nightmare. Your DNS host and your transactional email platform might share different information and lead you to do the wrong things.

This short post will explain how to send emails using a subdomain and how to update your DNS zone with GoDaddy in order to send verified emails.

Why using subdomains to send emails?

Deliverability and reputation are a big thing in regards to email. Say you’re sending order confirmations by email, you want these to arrive directly in your customers’ mailbox instead of spam folder.
Sending all your emails (sales, customer service, employee accounts…) from the same domain can be hurtful, especially if your own email are not received anymore by the people you’re trying to contact. It could quickly hurt your business and the response rate you’d get from cold leads to existing customers/partners you want to talk to.
Also a high amount of bounced email could cause your domain reputation to go down, including your SEO rank.

Subdomains are seen as separated entities on the web. If you have a high bounce rate with “mail.mydomain.com”, you will keep “domain.com” reputation intact and therefore, protect your deliverability. If you pay a close look to all your favorite apps that keep sending you emails, you’ll notice that their sender emails is usually a subdomain.

Configure your SPF / DKIM to authenticate your subdomain

Now that I know how to interpret values, It is going to sound easy, but trust me, after talking to three different customer service, including Google, I had to come up with the solution myself. Here we go:

1- Get your values from your transactional email platform

For example, in my case, I wanted to authenticate my subdomain with Mailjet and Front.
The values I was supposed to add in my DNS Zones where the following:

Values to enter in your DNS Zone : 2 TXT and one MX

Similarly with Mailjet, the TXT names were following a similar pattern:

  • subdomain.domain.com + value (for SPF/MX)
  • custom1._domainkey.subdomain.domain.com + value (for DKIM)

Unfortunately, copying and pasting these values into Godaddy, just didn’t work…I kept reading from both tools that my SPF and DKIM weren’t set…so here is what worked for me with GoDaddy.

2 – Configuring your DNS zone to send verified email from your subdomain

  1. Connect to your host, and edit your DNS Zone
  2. Add your subdomain as a CName, for example mail (name) and make sure it points to ‘@’ (value)
  3. Add a TXT record, that will be your SPF. The name of the TXT should be mail (and not mail.mydomain.com) or front-mail.mail instead of front-mail.mail.mobydish.com and the value will be something similar to v=spf1 include:sendgrid.net ~all.
  4. Add an MX record if needed. The name of this record should also just be mail (or front-mail.mail here), with a priority at 100 and poiting to mx.sendgrit.net
  5. Add a TXT record for your DKIM. only enter m1._domainkey.mail and its value containing your Pass key.

Voila! Hit Refresh and you should have a subdomain ready to be used for your transactional email!

Important information

  • If you’re setting up your SPF for your domain instead of subdomain, enter @ in the name input instead of mydomain.com
  • If you have multiple SPF value, make sure the name of each SPF is different to avoid conflict.
  • To summarize this post, remove ‘mydomain.com’ from any DNS record value provided by your platform

Hope that will help some of you out there. Feel free to ask questions if needed!

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