Compare Dovecot vs. Postfix vs. Sendmail

Dovecot stands out as a remarkable option for installations of any size, whether small or large. Notably, it ranks among the top IMAP servers, offering robust performance while seamlessly supporting both mbox and Maildir formats. Its mailboxes come with transparent indexing that enhances speed and retains full compatibility with traditional mailbox management tools. Adhering to industry standards, Dovecot successfully passes all compliance tests for IMAP servers, unlike many of its competitors that often fall short. One of its impressive features is the self-optimizing indexes, which provide just the necessary information that users typically require without excess. Additionally, Dovecot incorporates self-healing capabilities, autonomously addressing many issues it detects, such as corrupted index files, while ensuring that any problems encountered are logged for further investigation by administrators. Furthermore, Dovecot is designed with user-friendliness in mind, as it aims to present common error messages in a straightforward and comprehensible manner, making it easier for administrators to resolve issues. Overall, Dovecot's combination of performance, compliance, and user-centric features makes it a top-tier choice for email server solutions.

Postfix is a mail server developed by Wietse Venema, originally created at IBM research as a viable alternative to the popular Sendmail program, and Wietse continues to enhance and maintain it while working at Google. This robust mail server operates on various UNIX systems including AIX, BSD, HP-UX, IRIX, LINUX, MacOS X, Solaris, and Tru64 UNIX, requiring ANSI C, a POSIX.1 library, and BSD sockets for its functionality. Designed with speed, ease of administration, and security in mind, Postfix features an exterior reminiscent of Sendmail, yet its internal architecture is entirely distinct. Among its key capabilities are the support for multiple SMTP deliveries over a single TLS-encrypted connection, leveraging the existing tlsproxy(8) and scache(8) services, as well as the ability to utilize MySQL stored procedures. Moreover, Postfix implements a gradual degradation feature, allowing a daemon to log warnings and continue operation despite encountering some service issues, rather than terminating abruptly with a fatal error. Additionally, it can set the execute bit on a queue file, which is critical, as failure to do so would prevent any mail from being delivered successfully. This combination of features makes Postfix a versatile choice for mail server management.

The Sentrion platform from sendmail is crafted for intricate and expansive environments, yet we also offer a portion of this solution as open-source. While Sentrion may not suit everyone’s needs, it is an excellent choice for those employing open-source email systems within large and complex infrastructures, as it can support your messaging strategy for the long term, encompassing aspects like virtualization, consolidation, and cloud migration. The Domain Keys Identified Mail (DKIM) standard plays a pivotal role in email security by allowing senders to digitally sign their messages, enabling recipients to verify that these messages are genuine and have not been tampered with. This sender authentication process ensures that recipients can trace the origin of an email back to the sender's domain, providing assurance regarding the integrity of the message content. Utilizing cryptography, DKIM offers a widely accepted solution for reducing email fraud, thereby safeguarding an organization's brand and reputation while keeping implementation costs manageable. With the increasing prevalence of email threats, adopting DKIM can be a crucial step in fortifying your email security framework.