"spam" ile etiketlenmiş 3 gönderi

In Part 1 of this guide, we configured the firewall and opened the necessary ports for mail delivery. Now that we have made sure that messages are being sent from your server, we need to check that the DNS records are configured correctly. Gmail, Outlook, and other major mail services strictly verify MX, SPF, DKIM, DMARC, and PTR before delivering messages to the primary inbox. Correct records sharply increase the chance that messages will land in the Inbox folder instead of Spam (or be completely rejected).

In the following steps, we will describe how to check the current DNS records of each type and provide recommendations on how to configure them correctly.

Reliable email delivery to the recipient depends not only on the mail server itself, but also on correct DNS records and firewall configuration. If something is wrong with those, your messages are very likely to land in the Spam folder - or not be delivered at all.

This article outlines the key steps that will allow you to achieve nearly 100% reliable delivery of messages sent from your server. In Part 1, we will walk through the possible firewall-related issues in detail; in Part 2, you will find instructions for configuring DNS records.

The information in this article applies only to mail servers running on Linux distributions. Debian 12 and Rocky Linux 8.10 with the FASTPANEL control panel are used as examples.

Introduction​

If you have ever configured a mail server or encountered reverse DNS checks for other reasons, you have likely heard about PTR records. But what exactly are they? Why can you often not set up a PTR record yourself? Let’s figure it out!