Using Mailgun for Email Delivery from a Subdomain

To send newsletters and transactional emails from your web application using Mailgun, you can configure a subdomain (e.g., subdomain.domain.tld). This guide will help you set up Mailgun correctly, even if your DNS provider does not allow MX records for subdomains.

Step 1: Subdomain Setup

Begin by creating a subdomain in your DNS settings. Ensure that you configure the DNS records as per the instructions provided in the Mailgun dashboard. Note that the MX record for receiving emails is optional and may not be feasible if your domain registrar restricts MX records to the main domain only.

Step 2: Avoiding Main Domain Configuration

If your main domain is already in use for regular email services managed by other servers, you can continue using your subdomain without configuring the main domain for Mailgun. This prevents any disruption to existing email services.

Step 3: Sending Emails

Once your subdomain is set up, you should be able to send emails using an address like mail@domain.tld. Most major email providers, including Gmail, Yahoo, and Hotmail, should accept these emails. However, you may encounter issues with some providers (e.g., mail.ru, freenet.de, arcor.de) that reject emails with error messages indicating that the sender's domain cannot be found.

Common Error Messages

• Sender address rejected: Domain not found
• Domain of sender address [...] does not exist.
• Unrouteable mail domain, verifying bounce failed
• Unroutable sender address

These errors typically arise due to the absence of an MX record for your subdomain, which is referenced in the bounce address.

Step 4: Resolving Bounce Address Issues

To overcome the bounce address issue without transferring your domain to a different registrar, consider configuring Mailgun to use a different bounce address that does not rely on your MX records. For instance, you can set up a bounce address like bounce-gibberish@mailgun.com instead of bounce-gibberish@domain.tld.

This adjustment can help ensure that your emails are delivered successfully without being rejected due to domain verification issues.

Conclusion

By following these steps, you can effectively use Mailgun to send emails from a subdomain while avoiding complications related to MX records. If you have further questions or need assistance, consult the Mailgun documentation or reach out to their support team.