Sending mail to GMX

At GMX we adhere to a strict no tolerance spam policy. Therefore, if you want to make sure that your emails are successfully delivered to our GMX users, you must comply with the guidelines below.

Important: Delivery issues will persist and our support team will be unable to assist until the administrator takes action to fully comply with our guidelines.


  • Make sure that your mail server and client time and date are correctly set as specified in RFC 5322.
  • Ensure that the following email headers included in your message are syntactically correct: Date, From, Sender, To.
  • Make sure that the following headers included in your email are limited to just one each: BCC, CC, Date, From, Sender, Subject, To.
  • Immediately remove hard bounced email addresses from your mailing list.
  • Make sure your mail server has a static IP address.
  • Ensure you have valid DNS records of your domain pointing to your IP address and valid reverse DNS records of your IP address pointing to your domain. You can check your DNS configuration here.
  • Verify that your domain has a properly configured MX or A record. You can check your MX configuration here.
  • Ensure your email server always sends a valid HELO/EHLO value (the fully-qualified domain name) as specified in RFC 5321. You can check your HELO here.
  • Verify that your mail server IPs are not listed on one of the lists.