Postfix SMTP client whitelisting

I run a Postfix + Dovecot email server for my personal email. Common setups include reject_unknown_reverse_client_hostname for SMTP clients to reduce invalid connections attempts, but this became a problem when my new metro wireless ISP assigned me an IP that has no PTR record, causing my mail server to reject my own local email client’s SMTP connections!

In this post I present two solutions: simply adding permit_sasl_authenticated to the SMTP client restrictions, or implementing a more complex but generic whitelist via check_client_access and a MariaDB (or MySQL) database table.

Testing self-hosted webmail packages

I’ve been using SquirrelMail for nearly a decade to interface with my self-hosted mail server (Postfix + Dovecot) from the desktop. It’s a clean and simple FOSS webmail with relatively easy customizations and a variety of plugins.

However, its aging nature and a combination of a few complaints finally motivated me to start searching for a replacement…