A Marketer's Field Guide to United Internet

United Internet, one of Germany’s leading ISPs and media companies, began as 1&1 EDV-Marketing in 1988, a company that specialized in marketing for IT services.  The company saw its most significant growth with the commercial adoption of the internet in the late 90s.  By the year 2003 United Internet had been created as the parent company that today, houses 1&1, GMX.de and Web.de under one roof.

1&1 has over 14 million paying customers, each with their own email account. Web.de has 15 million active accounts and GMX more than 16 million. It’s worth noting that each GMX user can register up to 10 individual email accounts. In all, United Internet claims 46 million email users as of 2014, making them one of Europe’s largest email providers. United Internet, while a global player with entities like the American portal mail.com, has been very active in marketing its services in Germany, and capitalized on its German roots by launching “Email Made in Germany” in 2013, in response to the Snowden revelations of the US National Security Agency’s secret cyber monitoring.

All four email services (Web, GMX, 1&1 and mail.com) operate on the same platform but each service can (and does) apply their own policies for receiving mail into their network. This means that what works well for you, the sender, at GMX may not yield the same results when you send identical campaigns to 1&1 or Web.de.

I spoke with the Postmasters from United Internet and asked them what advice they would give senders who mail to their platform. Here is what they had to say;

List Acquisition and Sign-Up:

They require confirmed opt-in and are very strict about it! Failure will lead to blacklisting of the offending IP and the IP will only be removed if the implementation of this technique has been verified by the Postmaster team manually which is, according to one of the United Internet Postmasters, “very time consuming”. For the sender that means that if you’re blacklisted for failing to use confirmed opt-in, it could take quite a while before your mails will be delivered again.

What is Spam?

In United Internet’s view, spam is any mail that a user doesn’t want to receive. In fact, if the user can demonstrate that they continued to receive mail from a sender, even after requesting that the mail stop, GMX reserves the right to block the sender’s IP permanently. This is a manual process and the decision is made by the abuse desk team, it’s not automatic or based solely on TIS (“this is spam”) complaints.

Whitelisting & Feedback Loops

United Internet participates in the Certified Senders Alliance, a program created by the German Direct Marketing Association in cooperation with United Internet. CSA members benefit from the program’s German-centric coverage; The CSA whitelist covers half of the German market in terms of total mailboxes reached. As a sender, it’s important to keep on top of who doesn’t want your mail, not everyone takes the time to unsubscribe so monitoring complaints via a FBL (feedback loop), when available, can be very helpful. United Internet doesn’t currently offer this kind of FBL but may in the future.

Reminder Mails:

Send no more than three mails in total, regardless of the time frame.

Connection & Throughput:

The United Internet Postmasters strongly suggest that senders open no more than five, simultaneous connections when sending. They are flexible on throughput so use your discretion and be reasonable. If you are sending too many messages too quickly, expect to receive a 421 throttling message.

Use of Images: There are no policies or special requirements around use of images but mail that lands in the spam folder will have images blocked. If the user moves the mail back to the inbox the images will automatically display. Users can also specify whether or not they want mails that land in the spam folder to display images automatically.

Communicating with the Postmasters:

They strongly suggest that senders read their postmaster pages first:




Regarding senders reaching out to the Postmasters for support United Internet told me; “We need the complete error message provided by our server in case something went wrong during SMTP conversation. We also need the complete header if the mail has accidentally been flagged as spam. Furthermore, we don’t necessarily need the content (especially if it contains sensitive information) but it will help us resolving the issue.” They also need the IP address of the sending server in every case and say that “providing all of the above will improve response times greatly.”

The Perfect Sender:

When asked, “How would you describe the perfect sender?” one Postmaster replied, “We are very RFC compliant and require our senders to obey these rules.  Often we have to educate administrators about basic mail server configuration. Check this first before asking us for assistance.”


– Obey RFCs

– Use TLS

– Use confirmed opt-in

– Provide click-able and simple opt-outs as well as a List-Unsubscribe header.

– Monitor your reputation

– Keep your address lists up to date

In closing I would like to add the following, I’ve had the chance to get to know, the staff at United Internet, and they are some of the most responsive, helpful email experts in the European market. They’ve created some informative postmaster help sites (listed above)for senders so take advantage of them, follow their advice and here’s to successful emailing in 2015!


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