ubuntu

How To Monitor Server Health with Checkmk on Ubuntu 20.04 — step-by-step Linux tutorial on Progressive Robot

How To Monitor Server Health with Checkmk on Ubuntu 20.04

Checkmk is a monitoring solution that is both robust and simpler to install than many of its competitors. It is a self-contained software bundle that combines Nagios (a popular and open-source alerting service) with add-ons for gathering, monitoring, and graphing data. It also comes with Checkmk’s web interface — a comprehensive tool that addresses many of Nagios’s shortcomings. In this guide we will set up Checkmk and monitor two separate hosts: an Ubuntu 18.04 server and a CentOS 7 server.

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Ubuntu 20.04 — pyyaml — vulnerability — patch and remediation guide — diagnosis and fix on Ubuntu 20.04

Ubuntu 20.04 — pyyaml — vulnerability — patch and remediation guide

🟢 Low   ⏱ 5–15 min  Last verified: 25 May 2026 Affected versions: Ubuntu 20.04 (focal) 📖 ~4 min read  •  Source: Ubuntu Security Notice USN-4940-1 Related CVEs: CVE-2020-14343 Upstream summary: It was discovered that PyYAML incorrectly handled untrusted YAML files with the FullLoader loader. A remote attacker could possibly use this issue to execute […]

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Ubuntu 18.04 — gsl — vulnerability — patch and remediation guide — diagnosis and fix on Ubuntu 18.04

Ubuntu 18.04 — gsl — vulnerability — patch and remediation guide

🟢 Low   ⏱ 5–15 min  Last verified: 25 May 2026 Affected versions: Ubuntu 18.04 (bionic) 📖 ~4 min read  •  Source: Ubuntu Security Notice USN-6472-1 Related CVEs: CVE-2020-35357 Upstream summary: It was discovered that GNU Scientific Library incorrectly handled certain inputs. If a user or an automated system were tricked into opening a specially […]

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Ubuntu 14.04 — libnet-cidr-perl — vulnerability — patch and remediation guide — diagnosis and fix on Ubuntu 14.04

Ubuntu 14.04 — libnet-cidr-perl — vulnerability — patch and remediation guide

🟢 Low   ⏱ 5–15 min  Last verified: 25 May 2026 Affected versions: Ubuntu 14.04 (trusty) 📖 ~4 min read  •  Source: Ubuntu Security Notice USN-8110-1 Related CVEs: CVE-2021-4456 Upstream summary: Dave Rolsky discovered that Net-CIDR did not properly sanitize IP addresses. An attacker could possibly use this to bypass IP-based restrictions. Table of contents […]

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Ubuntu 20.04で認証局(CA)をセットアップおよび設定する方法 — step-by-step Linux tutorial on Progressive Robot

Ubuntu 20.04で認証局(CA)をセットアップおよび設定する方法

Ubuntu 20.04で実行するプライベート認証局は、クライアントとサーバー間の暗号化された接続を必要とするプログラムを設定、テスト、および実行できます。プライベートCAを使用して、インフラストラクチャ内のユーザー、サーバー、または個々のプログラムとサービスの証明書を発行できます。プライベートCAは、すべての開発、ステージング、および本番環境で同様のアーキテクチャと設定を使用できるようにするのに役立ちます。

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Common Problems 117432

Ubuntu 20.04 LTS – netplan apply fails due to YAML syntax error – Fix & Prevention

🟠 High   ⏱ 5–30 min  Last verified: 19 May 2026 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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How To Troubleshoot Common Apache Errors — step-by-step Linux tutorial on Progressive Robot

How To Troubleshoot Common Apache Errors

There are three main commands, and a set of common log locations that you can use to get started troubleshooting Apache errors. Generally when you are troubleshooting Apache, you will use these commands in the order indicated here, and then examine log files for specific…

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