Postfix
An SMTP transport and queue manager. Assemble authentication, mailbox storage, and client access explicitly; Postfix alone is not an IMAP service or a parsed-email webhook product.
Start with the first guide, then choose a sending, receiving, or feedback task. Each walkthrough identifies permissions, operational checks, and the boundary between the service and MailKite. Refer to the official Postfix documentation for current platform requirements.
Explore the guides
Install Postfix on an Ubuntu test server
Install the distribution package, choose a local-only starting configuration, and inspect Postfix before configuring an Internet-facing mail domain.
Configure a Postfix domain without opening relay access
Set the SMTP host identity, local destinations, and relay boundary before accepting mail for a test domain.
Separate Postfix submission authentication from Internet SMTP
Choose a SASL backend, require TLS for credentials, and distinguish application submission from upstream smarthost authentication.
Inspect Postfix deferred delivery before retrying mail
Read queue state and failure reasons, correlate the correct instance, and avoid destructive queue clearing or repeated global flushes.