Networking

How to Set Up Dovecot IMAP Server on Debian 9 — step-by-step Debian 9 tutorial on Progressive Robot

How to Set Up Dovecot IMAP Server on Debian 9

Introduction How to Set Up Dovecot IMAP Server on Debian 9 is a fundamental operation for any administrator maintaining a Debian 9 Stretch server. Debian 9 Stretch ships with the Linux 6.12 kernel, updated toolchains, and a fully refreshed package archive — meaning version numbers, configuration file paths, and some dependency chains differ from Debian […]

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Common Problems 125213

Oracle Linux 8 – Common Problem 025 – Diagnosis and Fix

🟡 Medium   ⏱ 5–30 min  Last verified: 17 February 2021 Affected versions: Oracle Linux 8 📖 ~3 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 […]

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Common Problems 117541

Ubuntu 20.04 LTS – UFW policy change blocks SSH and remote administration – Fix & Prevention

🔴 Critical   ⏱ 5–30 min  Last verified: 17 February 2021 Affected versions: Ubuntu 20.04 LTS 📖 ~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 […]

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Common Problems 115101

RHEL 8 multipathd Path Flapping Producing Intermittent IO Delays

🟡 Medium   ⏱ 5–30 min  Last verified: 17 February 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 Set Up a Bond Network Interface on Oracle Linux 8 — step-by-step Oracle Linux 8 tutorial on Progressive Robot

How to Set Up a Bond Network Interface on Oracle Linux 8

Introduction Setting up set up a bond network interface on oracle linux 8 on a Oracle Linux 8 server is a common task for system administrators, DevOps engineers, and site reliability engineers. This guide explains how to Set Up a Bond Network Interface on Oracle Linux 8, with all the commands you need, the SELinux […]

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How to Enable AppArmor on Debian 9 — step-by-step Debian 9 tutorial on Progressive Robot

How to Enable AppArmor on Debian 9

Introduction Deploying enable apparmor on debian 9 on a Debian 9 Stretch 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 Before you begin, ensure […]

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How to Deploy an Application to Kubernetes on RHEL 7 — step-by-step RHEL 7 tutorial on Progressive Robot

How to Deploy an Application to Kubernetes on RHEL 7

How to Deploy an Application to Kubernetes on RHEL 7 Deploying applications to Kubernetes involves more than simply running a container — it means defining how many replicas should run, how the application is exposed to network traffic, how it recovers from failure, and how updates are rolled out without downtime. Kubernetes provides two core […]

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Common Problems 115056

RHEL 8 Postfix Mail Queue Stuck Due To DNS And Firewall Constraints

🟡 Medium   ⏱ 5–30 min  Last verified: 16 February 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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Common Problems 114928

RHEL 8 Firewalld Blocks Application Port After Policy Change

🟡 Medium   ⏱ 5–30 min  Last verified: 16 February 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 Set Up OpenVSwitch on Oracle Linux 8 — step-by-step Oracle Linux 8 tutorial on Progressive Robot

How to Set Up OpenVSwitch on Oracle Linux 8

Introduction Setting up set up openvswitch on oracle linux 8 on a Oracle Linux 8 server is a common task for system administrators, DevOps engineers, and site reliability engineers. This guide explains how to Set Up OpenVSwitch on Oracle Linux 8, with all the commands you need, the SELinux and firewalld considerations to keep in […]

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