Red Hat System Administration II (RH134) – RHEL 10 — Lesson 3: Networking, Firewalls, SELinux, SSH, and Service Security

Learning Objectives

• Explain the structures, services, data, settings, roles, and dependencies governing network profiles and firewalld rules.
• Implement and validate SELinux contexts, SSH hardening, and service access control using reviewable evidence.
• Evaluate the condition where operators cannot explain the outcome because logs, commands, settings, and acceptance evidence were not captured consistently and select a proportionate corrective response.

Detailed Topics

• network profiles applied to the course scenario, expected platform behavior, dependencies, controls, and evidence.
• firewalld rules applied to the course scenario, expected platform behavior, dependencies, controls, and evidence.
• SELinux contexts applied to the course scenario, expected platform behavior, dependencies, controls, and evidence.
• SSH hardening applied to the course scenario, expected platform behavior, dependencies, controls, and evidence.
• service access control applied to the course scenario, expected platform behavior, dependencies, controls, and evidence.

Instructor Demonstration

The instructor traces a systems team hardening and extending a RHEL environment while preparing administrators for independent production support. The walkthrough connects navigation, commands, configuration logic, system messages, and evidence captured in the advanced RHEL administration lab book, recovery procedures, security evidence, and RHCSA readiness checklist. It also tests the exception where operators cannot explain the outcome because logs, commands, settings, and acceptance evidence were not captured consistently.

Hands-On Exercise

Complete a controlled Red Hat exercise covering Networking, Firewalls, SELinux, SSH, and Service Security and preserve the verified result in the advanced RHEL administration lab book, recovery procedures, security evidence, and RHCSA readiness checklist.

1. Confirm scope, prerequisites, versions, identities, dependencies, and acceptance criteria.
2. Execute the workflow while recording commands, settings, outputs, events, and system messages.
3. Test normal behavior, one boundary condition, and the stated exception.
4. Document corrections, evidence, ownership, retest criteria, rollback, and handover actions.

Scenario Analysis

• Identify which object, service, policy, setting, or sequence most strongly influences network profiles.
• Compare two defensible responses and explain technical, security, operational, and support trade-offs.
• Determine how the advanced RHEL administration lab book, recovery procedures, security evidence, and RHCSA readiness checklist should be approved, retained, retested, and updated.

Troubleshooting Guidance

Start where expected behavior first differs from the observed result. Check prerequisites, identity, configuration order, version compatibility, connectivity, status, resource limits, and evidence separately. Treat “operators cannot explain the outcome because logs, commands, settings, and acceptance evidence were not captured consistently” as a hypothesis until commands, logs, settings, and retest outcomes confirm the cause.

Validation Checklist

• Required platform components, identities, permissions, settings, and dependencies are present.
• The advanced RHEL administration lab book, recovery procedures, security evidence, and RHCSA readiness checklist connects each conclusion to objective, reviewable evidence.
• Normal processing, a boundary condition, dependency behavior, and the stated exception were tested.
• Corrections, ownership, retest criteria, rollback, documentation, and operational handover are complete.

Lesson Outcome

Learners can apply Networking, Firewalls, SELinux, SSH, and Service Security, explain the resulting platform behavior, and defend the outcome through the advanced RHEL administration lab book, recovery procedures, security evidence, and RHCSA readiness checklist.