Configure DNS SPF Records IP Properly for Email Deliverability

by | Sep 14, 2025 | Misc | 0 comments

The IP addresses used in an SPF record should be the public IP addresses of the actual mail servers that send email for the domain — not just the domain IP or website IP.

  • If your mail server is running on the same IP as your domain (e.g., mail.coupon-delivery.com resolves to 74.208.71.19), then you can use that IP address in the SPF record.
  • Alternatively, instead of listing IP addresses explicitly, you can use the a: mechanism with the mail server’s fully qualified domain name (FQDN) that resolves to the sending server’s IP. For example:
    a:mail.coupon-delivery.com dynamically points to the IPs the DNS resolves for that hostname.
  • The SPF mechanism ip4: or ip6: specifies the literal IP addresses allowed to send mail for the domain.

In summary:

  • If the mail server IP is static and you want a direct listing, use ip4: or ip6: with the mail server IP.
  • If the mail server hostname is stable and you expect IP changes, use a: with the mail server FQDN.
  • Both work fine, but using the FQDN (a:) offers easier maintenance if the IP changes.

For your setup, the SPF record includes IP addresses of servers authorized to send mail on behalf of your domains (not the domain IP of the website if different).

So the 74.208.71.19 and others you see in your SPF are the public IPs of your mail servers, not just the domain or website IP.

The IP addresses listed in your SPF record should be the public IP addresses of the mail servers that actually send email on behalf of your domains, not just the general domain or website IP.

In your case, the IPs like 74.208.71.19 are those public mail server IPs. Alternatively, you could use the a: mechanism with your mail server’s fully qualified domain name (for example, a:mail.coupon-delivery.com), which dynamically authorizes whatever IP that hostname resolves to.

Using literal IPs (ip4:) specifies exactly which IP addresses are authorized to send mail, while using hostnames (a:) offers easier maintenance if the mail server IP changes.

So the SPF example you have includes the public mail server IPs, not just the domain’s website IP.

it is best practice to use the public IP addresses of the actual mail servers that send your emails in the SPF record, regardless of the IP address your main domain or website is hosted on. This is because SPF needs to authorize precisely which servers (by their sending IPs) are allowed to send email on behalf of your domain.

  • If your mail server has a dedicated or static IP address, you list that IP (e.g., with ip4:).
  • The domain’s website IP or hosting IP does not necessarily correlate with your mail sending IPs and should not be used unless that same server sends mail.

This approach ensures SPF validation checks the correct sending IPs and helps prevent spoofing or mail rejection by recipient servers.

Summary:

  • Use mail server IPs in SPF, not website hosting IPs (unless they coincide).
  • Dedicated mail server IPs help maintain clearer and more effective SPF records.
  • This applies across all your domains that send mail through these servers.