Successful and secure e-mail communication

In this blog post, find out why sending e-mails from an e-mail subdomain is a worthwhile strategy for reaching your customers’ inboxes.

E-mail marketing is an online marketing channel that is used every single day. To make sure your e-mails land in the recipient’s inbox, you should use the available configuration options to optimize deliverability. The global spread of spam and the defensive measures taken by Internet service providers mean that companies have to be active to ensure the successful delivery of their newsletters and transaction e-mails and take care of technical measures.

Here, we are mostly talking about newsletters of an advertising nature, i.e. mass mailings to one distribution list (one-to-many), and transaction e-mails (one-to-one) sent from e.g. a CRM or a shop system to individual recipients.

The actual dispatch of such e-mails is often outsourced to specialist service providers with their own software solutions.

Subdomain

One thing that applies to all mailings is that the deliverability of the e-mails can be optimized using technical configurations. That includes using a subdomain for the dispatch – and this will be addressed in greater detail here.

It is highly advisable not to use a main domain for dispatching newsletters or transaction e-mails. This is strongly recommended in order to avoid potential reputational damage for the main domain, as every subdomain builds its own reputation. A main domain is the same domain as that of the company itself, via which the website can be found.

A subdomain follows the syntax “subdomain.maindomain.tld” and is configured on the name server (DNS) of the main domain. Simply put, a domain name server ensures that technical IP addresses are translated into addresses that we are familiar with.

As a practical example, let’s take a look at the Postshop and PostBus newsletters. For these newsletters, the subdomains “mails.post.ch” and “news.postauto.ch” have been configured.

While there are no limits on creativity for the choice of name for the subdomain, we advise our customers to use a distinct and self-explanatory choice of words when configuring a subdomain. For example, service, info, mail, news, newsletter, shop – depending on what best suits the intended use and how you wish to differentiate various types of e-mails and communication channels from each other.

Reputational damage

The main reason why subdomains are important for e-mail marketing is that they can establish a reputation separate to the parent domain. Establishing a reputation with providers such as Bluewin, Sunrise, GoogleMail or GMX is a many-layered process which, besides the technical factors mentioned here, also involves aspects relating to the content of an e-mail and the reaction of recipients.

Reputational problems or even reputational damage can occur if an e-mail dispatch domain is marked as spam or blacklisted. This can happen, for example, if you unknowingly write to a spam trap. If you don’t dispatch the e-mails via a subdomain but instead use the main domain, the company’s and brand’s entire communication activity may be put at risk. In the worst case scenario, the e-mail service provider can block you as a sender and you may not even be able to deliver normal business e-mails.

Procedure for e-mail authentication (SPF, DKIM, DMARC)

For reputational reasons, we advise always using a dedicated subdomain to dispatch newsletters or transaction e-mails and authenticating your own identity as a trustworthy sender using the Sender Policy Framework (SPF), DomainKeys Identified Mail (DKIM) or Domain-based Message Authentication, Reporting and Conformance (DMARC) authentication procedures.

A detailed explanation would need a whole blog post of its own, but in short:

• SPF (Sender Policy Framework) checks the authenticity of the sender address and ensures that only authorized senders can send e-mails from the configured domain.
• DKIM (DomainKeys Identified Mail) signs e-mails and ensures that the content and header of the e-mails cannot be manipulated.
• DMARC (Domain-based Message Authentication, Reporting and Conformance) specifies what should happen with e-mails sent from your domain for which authentication using SPF or DKIM failed.

Dispatch via service providers requires (full) domain alignment

Typically, an external software solution is used for bulk mailing and the dispatch is not carried out via mail servers in the company’s own infrastructure. The external service provider for the e-mail marketing tool usually stays hidden, as the recipients only see the configured subdomain of the company as the sender address and in the tracking or opt-in links.

A prerequisite for optimizing deliverability using authentication with SPF, DKIM and DMARC is “domain alignment”. The easiest way to implement domain alignment and optimize your deliverability is to delegate your subdomain to your service provider. Alternatively, you can make the required entries yourself, however, you will need expertise in DNS configuration.

Domain alignment is when the domain of the visible sender address (the “FROM address”) and the domain of the technical sender address (the “MAIL FROM address”) − often also referred to as the return path or bounce address − are aligned and refer to the same subdomain.

All of this facilitates the implementation of the e-mail security mechanisms presented here and leads to higher delivery rates, greater credibility and falsification prevention.