Webspace: Optimizing the delivery of e-mails
This guide was created with the following products:
(Details may vary with products from different providers but the main concepts remain the same)
Introduction
Do you run a mail service on your web space and notice that some emails aren't being delivered successfully? Then you're in the right place. There are various aspects that need to be considered to ensure reliable email traffic. In this guide, you will learn about key factors that influence email delivery in order to improve the reliability of your emails.
Blacklisting
In cases of misconduct (abuse), it can happen that certain providers blacklist and thus block the IP address of the email server. The consequence is that emails can no longer be delivered successfully or are marked as dangerous/spam. As a provider, we are always striving to proactively prevent such misconduct and to block incoming abuse reports to our customers' webspace as quickly as possible.
To minimize the risk of being blacklisted, we implement security measures, including monitoring mail traffic for suspicious activities and enforcing spam filters.
Should our webspace instances still be blacklisted by certain providers, we immediately contact them to resolve the situation as quickly as possible.
If smooth and reliable email delivery is crucial for you, choosing a service with a dedicated IP address is the better decision. Depending on the size and complexity of your project, we recommend using a VPS, Root Server, or Dedicated Server for this purpose.
Compliance with Content & Safety Standards
Adhering to content and security standards is a crucial aspect of operating a mail server to ensure the integrity, availability, and confidentiality of transmitted data. These standards encompass a wide range of practices and protocols designed to protect the mail server from unauthorized access, misuse, and other security threats. You can learn more about this in the following Identification Standards and Content Measures sections.
Identification Standards
Identification standards make the work of email providers and mail servers easier by helping to ensure the credibility of the sender. To prove that you are authorized to send emails on behalf of a domain, three important identity standards have been established: the SPF standard, the DKIM standard, and the DMARC standard.
SPF (Sender Policy Framework): SPF helps prevent email spoofing by specifying which IP addresses are authorized to send emails on behalf of a domain. For example, you can set up an SPF record in your DNS settings for your domain "example.com" to define which mail servers are allowed to send emails from "@example.com." If an email is sent from an unauthorized server, the recipient's mail server can flag it as suspicious or reject it.
DKIM (DomainKeys Identified Mail): DKIM adds a digital signature to the email header, which helps verify that the email has not been altered during transit and indeed comes from the specified domain. For example, if you send an email from "yourdomain.com," the DKIM signature ensures that the content of the email has not been tampered with and confirms the authenticity of the domain. The recipient's mail server uses this signature to check the integrity of the email.
DMARC (Domain-based Message Authentication, Reporting & Conformance): DMARC builds on SPF and DKIM by adding an additional layer of protection. It allows domain owners to specify how emails that fail SPF or DKIM checks should be handled (e.g., quarantined or rejected). For instance, if your domain has a DMARC policy set to "reject," any email that fails SPF or DKIM checks will be rejected by the recipient's mail server. Additionally, DMARC provides reports to domain owners, showing how their domain is being used in emails and helping monitor potential misuse.
Content Measures
The content of emails also plays a significant role. It’s important to achieve a balanced text-to-image ratio. Additionally, avoid using critical content such as videos, JavaScript, or forms, as these can trigger spam filters or cause delivery issues. Furthermore, each email should include an option to unsubscribe and an imprint at the end.
Other best practices include using clear and concise language, avoiding overly aggressive sales messages, and ensuring that the email is optimized for mobile devices.
Testing measures and reliability
There are various services available that can test the reliability of your email traffic. These services not only identify problems but also explain the reasons behind them and offer suggestions for improvement. Recommended providers for this purpose are mail-tester.com and mailgenius.com.
To perform the test, you send an email to the address provided by these services. They analyze all relevant information, and you can then view the results on their website. These tools are particularly valuable for ensuring that your emails are properly configured, improving deliverability, and avoiding common issues that could lead to your emails being marked as spam.
Conclusion
If you have followed and successfully implemented all the recommendations, you should now be in a much better position regarding the security and reliability of your email delivery. Your emails will not only have a higher likelihood of being delivered, but they will also be protected from unauthorized access and misuse.