Networking

Common Problems 115092

RHEL 8 Cockpit Web Console Unreachable from Network

🟡 Medium   ⏱ 5–30 min  Last verified: 15 June 2020 Affected versions: 8.5 8.6 8.7 8.8 8.9 8.10 📖 ~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 & […]

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Common Problems 112463

Windows Server 2019 — DHCP scope exhaustion caused by stale reservations and delayed lease reclamation — Fix & Prevention

🟠 High   ⏱ 5–30 min  Last verified: 14 June 2020 Affected versions: Windows Server 2019 📖 ~2 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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How to Install Ruby on Rails on Debian 10 — step-by-step Debian 10 tutorial on Progressive Robot

How to Install Ruby on Rails on Debian 10

Introduction How to Install Ruby on Rails on Debian 10 is a fundamental operation for any administrator maintaining a Debian 10 Buster server. Debian 10 Buster 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 10. […]

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How to Use journalctl for Systemd Log Analysis on RHEL 8 — step-by-step RHEL 8 tutorial on Progressive Robot

How to Use journalctl for Systemd Log Analysis on RHEL 8

The journalctl command is the primary interface for querying and browsing logs collected by systemd-journald on RHEL 8. Unlike traditional syslog files, the systemd journal stores structured, binary log data that can be filtered by unit, priority, time range, PID, and more. Mastering journalctl allows administrators to diagnose service failures, track kernel events, and export […]

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Common Problems 115004

RHEL 8 SSH Login Slow Due to DNS and GSSAPI

🟡 Medium   ⏱ 5–30 min  Last verified: 13 June 2020 📖 ~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 Install Kibana on Debian 9 — step-by-step Debian 9 tutorial on Progressive Robot

How to Install Kibana on Debian 9

Introduction This guide explains how to Install Kibana on Debian 9 on Debian 9 Stretch. Debian Stretch 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 9 install with the standard repositories […]

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How to Set Up VLAN Tagging on Debian 10 — step-by-step Debian 10 tutorial on Progressive Robot

How to Set Up VLAN Tagging on Debian 10

Introduction How to Set Up VLAN Tagging on Debian 10 is a fundamental operation for any administrator maintaining a Debian 10 Buster server. Debian 10 Buster 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 10. […]

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How to Install and Configure Consul for Service Discovery on RHEL 7 — step-by-step RHEL 7 tutorial on Progressive Robot

How to Install and Configure Consul for Service Discovery on RHEL 7

How to Install and Configure Consul for Service Discovery on RHEL 7 As applications grow beyond a single server, tracking where every service is running — and whether it is healthy — becomes a significant operational challenge. Consul, developed by HashiCorp, is a distributed, highly available service mesh and service discovery tool that solves this […]

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Common Problems 115538

RHEL 7 firewalld Rich Rule Order Breaks DNAT

🟡 Medium   ⏱ 5–30 min  Last verified: 12 June 2020 📖 ~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 Audit Security with Lynis on FreeBSD 12 — step-by-step FreeBSD 12 tutorial on Progressive Robot

How to Audit Security with Lynis on FreeBSD 12

Introduction This guide explains how to Audit Security with Lynis on FreeBSD 12 on FreeBSD 12. FreeBSD uses the pkg(8) binary package manager, rc.conf(5) for service startup configuration, and pf(4) as its primary packet filter. There is no SELinux or AppArmor — instead, FreeBSD provides the MAC (Mandatory Access Control) framework and Capsicum for fine-grained […]

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