Now as in the previous blogs of the deliverability series, we have discussed a good amount of information about list hygiene, engaging content, IP/ domain reputation, spam filters, and others. In this blog, we’ll try to put some of the important factors such as sender authentication to consider in the sending server, especially if you are configuring your sending environment from the scratch.

Table of Contents

  1. IP and Domains
  2. Setup rDNS
  3. Email authentication (DNS records)
  4. DKIM (domain key identified emails)
  5. SPF (sender policy framework)
  6. DMARC (domain-based message authentication, reporting, and conformance)

IP and Domains 

In the previous blog, we discussed building and maintaining the reputation of originating IP and Domain. In this blog, we’ll concentrate on what other steps you need to take with the originating IP and domain, in order to configure your system properly for better delivery rates.

Setup rDNS 

rDNS or reverse DNS is opposite to forward DNS, and resolves the IP address to the domain name. As subscribers’ inboxes are flooded with spam and forged emails, ISPs (Including Major ISPs) take this very sensitively so that no email which looks illegitimate reaches the user’s inbox.

Let’s be simple on it without using technical terms. When your sending server connects to other systems to deliver an email, the other system looks like the originating IP resolves to the domain it claims to be coming from.

If the information successfully resolves to the right domain, the server would accept the incoming email. But in case of not being able to resolve to the sending domain, ISPs would suspect the incoming email and would not deliver it to the recipient.

Email Authentication (DNS Records) 

sender authentication | Mumara

Email authentications benefit both sender and the recipient (Recipient’s ISP). For the sender, it offers the opportunity to publish policies and announce the legitimacy of the email they are sending, while it provides the recipient with the ability to protect the inbox by getting swamped from unwanted and unsolicited emails.

DKIM (Domain Key Identified Emails)

This email security standard is an initiative to stop spam/forged emails to get success in the subscriber’s inbox. The pair of public and private keys help verify the message source to confirm that the message hasn’t been changed during transit.

When you set up your mail server, make sure you generate accurate DKIM value, a public key to be able to set up within the domain’s DNS panel, and a private key for the sending server.

SPF (Sender Policy Framework)

SPF also known as the sender policy framework offers the recipient server the ability to verify if the sending server is allowed to send on behalf of the sending domain. Like DKIM, SPF is also a TXT DNS entry, and primarily be used to control email spoofing by offering an extra security layer.

Implementing it right will make the recipient’s system recognize if the sending server is authorized to send an email on behalf of a particular domain. So unless your server isn’t configured with accurate SPF entry, your sending domain will most likely appear as forged to the ISPs, and your message will not be accepted.

DMARC (Domain-Based Message Authentication, Reporting, and Conformance) 

Like the earlier discussed email authentications, DMARC is intended to give the recipient’s side better control to judge the legitimacy of an incoming message, and the sending side an ability to publish policies to improve sending reputation and enhance effectiveness against spamming and spoofing.

DMARC | Mumara

One needs to have both DKIM and SPF in place before configuring the DEMARC. You are required to publish a TXT record in your domain’s DNS to configure the DMARC. The process can sometimes be tricky and may need technical assistance to get it configured correctly. Implementing the key values of DMARC, domain reporting, and domain alignment ensure that the email is authenticating its earlier setup values of DKIM and SPF.

For improved deliverability, make sure you have all these sender authentications and policies published correctly as recommended. If you don’t want your sending reputation to suffer from a drawback, go through the earlier discussed topics of the deliverability series.

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Eric Lee

A reader, writer, researcher, and explorer!

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