Mail Services

How to Manage Systemd Services and Units on RHEL 7 — step-by-step RHEL 7 tutorial on Progressive Robot

How to Manage Systemd Services and Units on RHEL 7

How to Manage Systemd Services and Units on RHEL 7 Red Hat Enterprise Linux 7 made a significant shift from the traditional SysVinit and Upstart initialization systems to systemd as the default init system. Systemd is a comprehensive system and service manager that controls how services start, stop, and interact with the rest of the […]

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How to Configure OpenDKIM with Postfix on Debian 11 — step-by-step Debian 11 tutorial on Progressive Robot

How to Configure OpenDKIM with Postfix on Debian 11

Introduction Deploying configure opendkim with postfix on debian 11 on a Debian 11 Bullseye machine is straightforward thanks to Debian’s policy-compliant packaging. Unlike rpm-based distributions, Debian stores configuration helpers in /etc/default/, uses update-rc.d for older init scripts, and provides dpkg-reconfigure for interactive package configuration. This tutorial stays on the systemd path throughout. Prerequisites You will […]

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How to Configure DKIM, SPF and DMARC on RHEL 8 — step-by-step RHEL 8 tutorial on Progressive Robot

How to Configure DKIM, SPF and DMARC on RHEL 8

Email authentication standards — SPF, DKIM, and DMARC — are the primary tools used by receiving mail servers to verify that messages claiming to come from your domain actually originate from your authorized infrastructure. Without them, your outbound mail is far more likely to land in spam folders or be rejected outright. On RHEL 8, […]

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How to Configure Postfix Mail Server on Debian 11 — step-by-step Debian 11 tutorial on Progressive Robot

How to Configure Postfix Mail Server on Debian 11

Introduction This guide explains how to Configure Postfix Mail Server on Debian 11 on Debian 11 Bullseye. Debian Bullseye uses systemd for service management, nftables as the underlying packet filter (with ufw or iptables front-ends still available), and AppArmor for mandatory access control. Every command is designed for a minimal Debian 11 install with the […]

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How to Install and Configure Dovecot IMAP Server on RHEL 8 — step-by-step RHEL 8 tutorial on Progressive Robot

How to Install and Configure Dovecot IMAP Server on RHEL 8

Dovecot is a high-performance, secure IMAP and POP3 server that works seamlessly alongside Postfix to deliver a complete mail server stack on RHEL 8. While Postfix handles sending and receiving mail via SMTP, Dovecot allows mail clients like Thunderbird or Outlook to retrieve messages using IMAP or POP3. Dovecot is also SELinux-aware and actively maintained, […]

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How to Install and Configure Postfix Mail Server on RHEL 8 — step-by-step RHEL 8 tutorial on Progressive Robot

How to Install and Configure Postfix Mail Server on RHEL 8

Postfix is a high-performance, security-focused Mail Transfer Agent (MTA) that ships with RHEL 8 and is the default replacement for Sendmail. It handles the delivery of outbound email and, when configured correctly, accepts inbound mail for local users. Understanding Postfix is foundational for any RHEL administrator who needs to send system alerts, application notifications, or […]

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How to Set Up a DNS Server with BIND9 on RHEL 8 — step-by-step RHEL 8 tutorial on Progressive Robot

How to Set Up a DNS Server with BIND9 on RHEL 8

Running your own DNS server gives you full control over name resolution for internal infrastructure and reduces dependency on external resolvers. BIND9 (Berkeley Internet Name Domain) is the most widely deployed DNS server in the world and is available in the default RHEL 8 repositories. On RHEL 8, the package is split into bind (the […]

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How to Configure a Static IP Address with NetworkManager on RHEL 8 — step-by-step RHEL 8 tutorial on Progressive Robot

How to Configure a Static IP Address with NetworkManager on RHEL 8

Assigning a static IP address ensures your RHEL 8 server is always reachable at a predictable address — essential for services like DNS, mail, or web hosting. On RHEL 8, NetworkManager is the default network management service and the preferred tool for making persistent network changes. Using nmcli from the command line lets you configure […]

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How to Automate Backups with rsync and cron on RHEL 8 — step-by-step RHEL 8 tutorial on Progressive Robot

How to Automate Backups with rsync and cron on RHEL 8

Reliable backups are the last line of defense against data loss from hardware failures, ransomware, or accidental deletion, and on RHEL 8 the combination of rsync and cron provides a powerful, scriptable, and dependency-free backup pipeline. rsync is a fast incremental file-transfer utility that only copies changed data, making it efficient for both local and […]

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How to Set Up Checksum Monitoring with AIDE on RHEL 8 — step-by-step RHEL 8 tutorial on Progressive Robot

How to Set Up Checksum Monitoring with AIDE on RHEL 8

AIDE (Advanced Intrusion Detection Environment) is a host-based intrusion detection tool that builds a cryptographic baseline of your filesystem and alerts you whenever files are added, removed, or modified. On RHEL 8 it is available in the base repositories and integrates cleanly with cron and email for automated daily checks. Unlike network-based intrusion detection, AIDE […]

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