Mail Services

How to Configure Prometheus AlertManager on RHEL 7 — step-by-step RHEL 7 tutorial on Progressive Robot

How to Configure Prometheus AlertManager on RHEL 7

How to Configure Prometheus AlertManager on RHEL 7 Prometheus collects and stores metrics, but on its own it cannot notify your team when something goes wrong. Alertmanager is the dedicated component that handles alert routing, deduplication, grouping, and delivery to receivers such as email, Slack, or PagerDuty. On RHEL 7, setting up Alertmanager alongside Prometheus […]

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How to Configure Postfix Mail Server on FreeBSD 13 — step-by-step FreeBSD 13 tutorial on Progressive Robot

How to Configure Postfix Mail Server on FreeBSD 13

Introduction FreeBSD 13 is a UNIX-derived operating system renowned for its network stack performance, ZFS integration, and Jail isolation primitives. Setting up configure postfix mail server on freebsd 13 on FreeBSD 13 follows the rc.conf/service(8) paradigm rather than systemd, which means enabling a service and configuring its startup options are done differently from any Linux […]

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How to Install Netdata on RHEL 8 — step-by-step RHEL 8 tutorial on Progressive Robot

How to Install Netdata on RHEL 8

Netdata is a lightweight, real-time performance monitoring agent that collects thousands of system and application metrics with per-second granularity and displays them through a built-in, zero-configuration web dashboard. Unlike heavier stacks, Netdata starts delivering useful insights within minutes of installation and requires virtually no ongoing maintenance. It can also stream metrics to a central parent […]

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How to Install and Configure Postfix Mail Server on RHEL 7 — step-by-step RHEL 7 tutorial on Progressive Robot

How to Install and Configure Postfix Mail Server on RHEL 7

How to Install and Configure Postfix Mail Server on RHEL 7 Postfix is a high-performance, security-focused Mail Transfer Agent (MTA) that is installed by default on many RHEL 7 systems. It handles the sending, receiving, and routing of email using the SMTP protocol. Whether you are setting up a server to send application alerts, relay […]

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Common Problems 115113

RHEL 8 Postfix cannot send mail due to firewall and SELinux policy

🟡 Medium   ⏱ 5–30 min  Last verified: 2 December 2021 📖 ~1 min read Table of contents Symptom & Impact Environment & Reproduction Root Cause Analysis Quick Triage Step-by-Step Diagnosis Solution – Primary Fix Solution – Alternative Approaches Verification & Acceptance Criteria Rollback Plan Prevention & Hardening Related Errors & Cross-Refs References & Further […]

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How to Monitor Active Directory on Windows Server 2016 — step-by-step Windows Server 2016 tutorial on Progressive Robot

How to Monitor Active Directory on Windows Server 2016

How to Set Up Windows Server 2016 Active Directory Monitoring Proactive monitoring of Active Directory on Windows Server 2016 ensures that authentication, replication, and policy application continue to function reliably. Unlike reactive troubleshooting, a monitoring framework surfaces problems before users report them, giving administrators time to remediate issues during business hours rather than during incidents. […]

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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 Configure OpenDKIM with Postfix on FreeBSD 13 — step-by-step FreeBSD 13 tutorial on Progressive Robot

How to Configure OpenDKIM with Postfix on FreeBSD 13

Introduction How to Configure OpenDKIM with Postfix on FreeBSD 13 is a core administration task for any FreeBSD 13 server operator. FreeBSD 13 ships with the 15.0-RELEASE kernel, ZFS as the default root filesystem, Capsicum capability sandboxing improvements, and an updated ports tree. Unlike Linux distributions, FreeBSD uses rc(8) for service management, pf for packet […]

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How to Configure Windows Server 2019 with PRTG — step-by-step Windows Server 2019 tutorial on Progressive Robot

How to Configure Windows Server 2019 with PRTG

How to Configure Windows Server 2019 with PRTG PRTG Network Monitor from Paessler is a comprehensive agentless monitoring solution that uses SNMP, WMI, and custom sensors to monitor Windows Server 2019 without requiring a local agent. PRTG communicates directly with Windows Management Instrumentation (WMI), which is built into Windows Server 2019, to collect CPU, memory, […]

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How to Use Prometheus Blackbox Exporter for Endpoint Monitoring on RHEL 7 — step-by-step RHEL 7 tutorial on Progressive Robot

How to Use Prometheus Blackbox Exporter for Endpoint Monitoring on RHEL 7

How to Use Prometheus Blackbox Exporter for Endpoint Monitoring on RHEL 7 The Prometheus Blackbox Exporter probes external endpoints over HTTP, HTTPS, TCP, ICMP, and DNS from the perspective of an outside caller, making it an essential complement to node-level metrics collected by Node Exporter. While Node Exporter tells you about CPU load and memory […]

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