Improve Inbox Placement and Email Deliverability: Technical Aspects (Part 1)

Anton Shabatov - February 6, 2018 - 0 comments

Email marketing has one main task – to ensure your audience receives your message. It can be a real challenge to reach your potential customer and if you also face this struggle, our guide will prove to be vital for your business. This guide is divided into three articles in order to cover the topic completely. Today, we will discuss the first topic that concerns the technical issues of email marketing.

1. Sign up email verification with real-time API.

Over time, every email list gets invalid addresses. It can happen due to the fact that that person is not engaged in your emails anymore and mark them as spam. That definitely has a negative impact on your inbox rate. Some people use “disposable” emails (like the Mail for Spam service) in order to get some perks after registration, but those addresses are not meant to be used for real email exchanges. We understand people who use such an option, but for email marketers, this can be a real problem.

Real-time free email verification helps you clean the list of invalid addresses. You will be able to check the receiver before sending an email and eliminate the “fake” signups. Such an approach is vital to reducing your bounce rate and improving deliverability. Real-time email validation confirms that you try to contact the interested subscribers.

2. Double opt-in confirmation: meaning and importance.

In email marketing, the addresser needs to request the allowance from the receivers to send them emails. In USA or Canada, there are special anti-spam laws that regulate this very thing. This is done via opt-in confirmation. The receiver gets the message like “By submitting this form, you agree to receive emails from our company.” So registration is the first sign that the person wants to get your emails.

Double opt-in means the receiver confirms this option by clicking on a link you send to their address. This feature helps to eliminate bots and occasional registrations. You get extra proof that the subscriber is interested in your offer. On their turn, the receiver can make an informed decision about whether or not they want to read your newsletters. They will more likely not mark your emails as spam.

3. DKIM authentication and its main principles.

Domain Keys Identified Mail, or DKIM proves that the letter was sent by a real owner of the domain. The company is responsible for the content of the message that was sent on its behalf. So with a personal domain key, you encrypt the domain’s outgoing email headers and add its public version to the DNS record. For example, users of G Suite can generate such a key, add it to the DNS records, and turn on mail signing in order to start adding DKIM to the messages. And if you have bought the domain from the Google partners, you can skip the second step.

This same option is provided by Yahoo as well. As in the case of SPF validation, if you use some mail delivery services, create a DKIM record specifically for each of them.

DKIM validation of the signatures ensures the receiver that the original message has not been changed or tampered with along the way. This process is a complicated one, so not every sender decides to use this method. Check the correctness of your DKIM using services like MX Toolbox or Protodave.

Note: one domain can have as many DKIM records as it needs.

4. The importance of SPF authentication.

Sender Policy Framework is an email authentication protocol. It helps to detect spoofing, and it is also used for proving that incoming letters from a particular domain are sent by a host chosen by a domain’s administrator.

How does it work? Companies send emails with SPF records in the DNS. That is how the list of authorized IPs is created, that is connected with emails from the dependable domains. An SPF check means verifying the SPF record from the domain name listed in the email address. If the domain is not found in the list of the SPF record, the letter does not pass the authentication of the mail control panel. Users of G Suite can automatically add an SPF record in their emails and then the receiver’s mail will not reject your message.

Take a look at the common reasons for errors in SPF records:

– Incorrect SPF records. It is better not to have this record at all than to use the wrong one. Otherwise, the mail system will block your email. Use Kitterman and MX Toolbox services to check the accuracy of your SPFs. Here is a guide on how to check the SPF record in your Gmail:
– Usage of third-party services (mail delivery or other services). Some marketers forget to take SPF records from these services or to add them to the SPF TXT statement. It may be an email delivery service or a billing service. Do not forget to collect their SPFs.

If you check the correctness of your SPF records and add data of the services you use in emailing then your letters will pass the check.

Important: there can be only one SPF record per domain.

5. DMARC authentication and its main principles.

In some cases, spammers can use your domain for sending spam to your email list. DMARC is used to protect subscribers and your reputation from phishing and spoofing. This authentication method is based on SPF and DKIM. This is how you can spot the unwelcome activity within your domain. One of the testing tools was already mentioned: MX Toolbox. You need to follow 5 steps to complete the implementation of DMARC:

– Do the verification of the domain alignment
– Choose the email account to get the reports
– Study the special tags of DMARC
– Create DMARC record via DMARC Creation Wizard
– Add the received record to DNS

G Suite users can benefit from Google and cooperation. So the account users can control the situation with the spam that can be sent using their domain. That means you can decide what actions to take in case of unwelcome emails detection. And if you use the third-party software for email delivery, share your DKIM key with those services as well.

6. The significance of a DNS provider with a good reputation.

The success of your email delivery depends on the reputation of the DNS server you use. It is an important element of commercial activity on the Internet. There are numerous features you can set up to adjust it to your business goals. Selecting a reputable DNS provider from the very beginning will prevent you from possible troubles in the future.

How does it correlate with emails? Your email address is based on the domain’s name. And you cannot handle all of the above-mentioned verifications without DNS. Here are some sources of dependable providers:
– DYN Managed DNS;
– Cloudflare.

7. PTR records for sending IPs.

As we already know, the DNS records point the particular domain to the selected IPs. PTP works in reverse – it connects the IP address with the selected domain. That is how this tool got its second name, “Reverse DNS Record.” The main task of PTR records is to display whether the IP is bonded to the definite domain.

This option is of current interest to outbound mailing servers. It can trace the origin of the sent letter as well as level up the credibility of this email server. Moreover, there are servers that refuse to receive emails from IPs without PTR records.

8. Usage of FBL service.

The crucial action in email marketing is to register to FBL (complaint feedback loop). You will be informed about receiver complaints such as hitting a spam button or adding your email to the junk folder. Some providers offer this option to help you keep your email list clean and prevent receivers from getting unnecessary letters.

Without such data, you may keep sending emails to people who are no longer interested in your messages, and it can negatively influence your reputation as well.


Taking into consideration these recommendations will help you in improving your inbox and deliverability. However, it is not enough for sure success. Stay tuned for the second part of the article about the technical aspects of mailing. Soon we will provide you with more useful information about the quality of the content and how to avoid being marked as spam.

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