Mass mailing is a multifaceted process that requires careful consideration and continuous refinement. It involves various factors and entails a trial-and-error approach. In this article, we will delve into the intricacies of mass mailing, focusing on the criteria used by reputable servers to evaluate incoming emails and the strategies employed to tailor the rate of sending.
2. The Process:
When a reputable server receives an email, it undergoes a series of evaluations to determine its legitimacy. Let’s explore some key criteria involved:
2a. IP Reputation:
The server checks if the sender’s IP is associated with a resolvable valid hostname.
Most of the ESPs integrate with Spamhaus/CSI (Proofpoint)/Barracuda etc, for blacklist check commenly referred to as SBL, XBL, or PBL (collectively known as the ‘Zen’ block list).
The presence of a PTR (Pointer) or rDNS (reverse DNS) record is also checked.
2b. Verification of Sender’s Legitimacy:
Additionally, to enhance email deliverability, prevent spoofing, and establish trust between senders and recipients. it verifies if the email aligns with the designated sender specified by SPF (Sender Policy Framework) and whether the message is digitally signed using DKIM (DomainKeys Identified Mail) along with the utilization of DMARC (Domain-based Message Authentication, Reporting, and Conformance).
Let’s explore each of them in detail:
2c. SPF (Sender Policy Framework):
SPF is an email authentication protocol that enables domain owners to specify which servers are authorized to send emails on their behalf. By publishing SPF records in their DNS settings, domain owners can define a list of approved IP addresses or domains that are permitted to send emails using their domain. When an email is received, the recipient’s server can check the SPF record to verify the authenticity of the sender. SPF helps combat email spoofing and prevents unauthorized entities from sending emails claiming to be from a particular domain.
2d. DKIM (DomainKeys Identified Mail):
DKIM is an email authentication method that adds a digital signature to outgoing emails. The sender’s domain signs the email using a private key, and the recipient’s server can validate the signature using the public key retrieved from the sender’s DNS records. DKIM ensures that the email has not been tampered with during transit and verifies that it genuinely originated from the claimed domain. It provides an additional layer of trust and helps prevent email forgery and spoofing.
2e. DMARC (Domain-based Message Authentication, Reporting, and Conformance):
DMARC is a policy-based email authentication protocol that builds upon SPF and DKIM. It allows domain owners to specify how email receivers should handle emails that fail SPF and DKIM checks. With DMARC, domain owners can set policies to determine whether failing emails should be quarantined or rejected outright. Additionally, DMARC enables domain owners to receive reports on email authentication results, providing valuable insights into email activity and potential abuse. DMARC helps protect domains from email spoofing and strengthens the overall security of email communication.
2f. BIMI (Brand Indicators for Message Identification):
BIMI is an emerging standard that allows senders to display their brand logos in the email recipient’s inbox. It requires the implementation of SPF, DKIM, and DMARC. When properly configured, BIMI enables email clients to display the sender’s brand logo alongside authenticated emails, increasing brand visibility and establishing trust with recipients. BIMI is an additional layer of authentication that enhances the visual recognition of legitimate senders and helps combat phishing attempts.
These email authentication mechanisms (SPF, DKIM, DMARC, and BIMI) collectively contribute to a more secure and trustworthy email ecosystem. Implementing these protocols helps prevent email spoofing, protects sender reputation, reduces the risk of phishing attacks, and improves the overall deliverability and user experience for legitimate senders and recipients alike.
Mass mailing is a complex endeavor that necessitates a deep understanding of the criteria used by reputable servers to evaluate incoming emails. It requires careful attention to IP reputation, tailoring the rate of sending, and employing effective strategies. By refining our approach and adhering to best practices, we can enhance the deliverability of our emails and establish positive relationships with recipients.