RHEL 7

Common Problems 115443

RHEL 7 – Legacy service Command Reports Running but Port Is Closed

🟡 Medium   ⏱ 5–30 min  Last verified: 29 December 2019 📖 ~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 Configure Mandatory Access Control with SELinux Policies on RHEL 7 — step-by-step RHEL 7 tutorial on Progressive Robot

How to Configure Mandatory Access Control with SELinux Policies on RHEL 7

How to Configure Mandatory Access Control with SELinux Policies on RHEL 7 SELinux (Security-Enhanced Linux) is a mandatory access control (MAC) framework built into the Linux kernel and deeply integrated into RHEL 7. Unlike discretionary access control (DAC), which is based on user and group ownership, SELinux enforces fine-grained access rules based on security contexts […]

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How to Configure Network QoS with tc on RHEL 7 — step-by-step RHEL 7 tutorial on Progressive Robot

How to Configure Network QoS with tc on RHEL 7

How to Configure Network QoS with tc on RHEL 7 Quality of Service (QoS) is the practice of managing network traffic to ensure that critical applications receive the bandwidth and latency guarantees they need. Linux provides a sophisticated traffic control subsystem accessible through the tc (traffic control) command, part of the iproute2 package. With tc, […]

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How to Sync Time with Chrony on RHEL 7 — step-by-step RHEL 7 tutorial on Progressive Robot

How to Sync Time with Chrony on RHEL 7

How to Sync Time with Chrony on RHEL 7 Accurate system time is critical for nearly every networked service on a Linux server. Log correlation, SSL certificate validation, Kerberos authentication, database replication, and distributed systems all depend on clocks that are closely synchronized across machines. Red Hat Enterprise Linux 7 ships with Chrony as the […]

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Common Problems 115597

SELinux File Context Drift After Manual Copy

🟡 Medium   ⏱ 5–30 min  Last verified: 25 December 2019 📖 ~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 Harden PHP on RHEL 7 — step-by-step RHEL 7 tutorial on Progressive Robot

How to Harden PHP on RHEL 7

How to Harden PHP on RHEL 7 PHP is one of the most widely deployed server-side languages in the world, and its default configuration is designed for convenience rather than security. On a production RHEL 7 server, leaving PHP at its defaults exposes your system to information disclosure, remote file inclusion, code injection, and privilege […]

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How to Configure Nginx Server Blocks (Virtual Hosts) on RHEL 7 — step-by-step RHEL 7 tutorial on Progressive Robot

How to Configure Nginx Server Blocks (Virtual Hosts) on RHEL 7

How to Configure Nginx Server Blocks (Virtual Hosts) on RHEL 7 Nginx server blocks — the equivalent of Apache virtual hosts — allow a single Nginx instance to serve multiple websites on the same server by routing requests based on the domain name or IP address. This is one of the most common Nginx configurations […]

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Common Problems 115467

NTP Drift Causes Authentication and TLS Errors

🟡 Medium   ⏱ 5–30 min  Last verified: 21 December 2019 📖 ~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 Two-Factor Authentication for SSH with Google Authenticator on RHEL 7 — step-by-step RHEL 7 tutorial on Progressive Robot

How to Set Up Two-Factor Authentication for SSH with Google Authenticator on RHEL 7

How to Set Up Two-Factor Authentication for SSH with Google Authenticator on RHEL 7 Password-based SSH authentication is vulnerable to brute-force attacks, credential stuffing, and phishing. Adding a second authentication factor — a time-based one-time password (TOTP) generated by an app like Google Authenticator or Authy — dramatically reduces this risk. Even if an attacker […]

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How to Install and Configure FreeIPA on RHEL 7 — step-by-step RHEL 7 tutorial on Progressive Robot

How to Install and Configure FreeIPA on RHEL 7

How to Install and Configure FreeIPA on RHEL 7 FreeIPA is an integrated identity and authentication solution that combines LDAP (via 389 Directory Server), Kerberos, DNS, a certificate authority (Dogtag PKI), and a web-based management interface into a single coherent platform. It is Red Hat’s upstream open-source project that underpins Red Hat Identity Management (IdM), […]

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