Tag: System Administration
Tag: System Administration
Section titled “Tag: System Administration”24 posts
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- Manage Process Limits with limits.conf and systemd This guide explains how to set nofile and nproc limits using limits.conf and systemd settings such as LimitNOFILE, and how to verify the effective values in different execution contexts for shells and services.
- Configure sysctl Temporarily and Persistently and Verify the Applied Values This guide explains how to temporarily change kernel parameters with sysctl, configure persistent settings with sysctl.d, and verify the requested and effective values as well as configuration conflicts.
- Managing Application Logs with logrotate This guide explains how to use logrotate to define application log rotation policies, decide when to use copytruncate, configure postrotate, perform dry-runs and forced tests, and safely prevent custom log files from growing excessively.
- Build a Minimal Packet Filter with nftables This guide explains how to build a minimal packet filter using nftables tables, chains, rules, counters, and persistence, and how to manage and verify it safely, including avoiding concurrent management with firewalld.
- Secure Initial Configuration of a Linux OpenSSH Server This guide explains how to improve the security of OpenSSH Server on Linux step by step by checking sshd_config, restricting root login, disabling password authentication, configuring AllowUsers, and reloading the configuration without losing access.
- Designing systemd Unit Dependencies and Startup Order This guide explains how to design dependencies and startup order between systemd Units using Wants, Requires, After, Before, and targets, and how to verify their behavior on an actual system when failures occur.
- systemd-journald Persistence, Capacity Limits, and Rotation This guide explains how to configure log persistence, capacity limits, and rotation using systemd-journald settings such as Storage, SystemMaxUse, and vacuum, and how to verify that logs are retained after a reboot.
- Verify RPM Package Signatures, Owned Files, and Modifications This article explains how to use the rpm command to check installed package signatures, owned files, file origins, and modification status, and how to investigate unknown files and package changes.
- Manage DNF Repositories and Module Streams This article explains how to check and manage DNF repositories, repoquery, module streams, versionlock, and cache to control package sources and installed versions as intended.
- Configuring and Troubleshooting Linux Time Synchronization with chrony This article explains how to configure Linux time synchronization with chrony, verify synchronization status with sources and tracking, use waitsync, persist the configuration, and isolate the causes of time drift by checking reachability.
- Investigating Listening Ports and Connection States with the ss Command This article explains how to use the ss command to check listening ports, associated processes, TCP states, and filter conditions, and how to troubleshoot port conflicts and connection failures from the server side.
- Practical Guide to firewalld Zones, Services, and Rich Rules This guide explains how to safely modify and verify a Linux firewall with firewalld without disrupting connectivity, while checking runtime/permanent settings, zones, services, source restrictions, and rich rules on an actual system.
- Linux Log Investigation and Retention Management with journalctl and systemd-journald This guide systematically explains how to search and investigate Linux logs and manage persistence, capacity control, and retention with journalctl and systemd-journald.
- Practical Guide to systemd Service Management and Unit Files A practical guide to service management with systemd, Unit file design, dependencies, automatic startup, restart on failure, safe configuration changes with drop-ins, and verification methods.
- Complete Guide to Linux File Ownership and Permission Design This guide systematically covers Linux file owners, groups, permissions, umask, and special bits, with practical explanations of how to design secure access rights and troubleshoot permission problems.
- Extracting Log Files with PowerShell A practical guide to extracting specific log data using PowerShell on Windows systems.
- Managing Task Scheduler with schtasks.exe This article explains how to administer the Windows Task Scheduler using schtasks.exe It covers subcommands, core options, daily and monthly schedules, event-driven execution, and XML template management
- Commands to View and Configure Windows Environment Variables A structured guide to viewing, configuring, and persisting Windows environment variables using CMD and PowerShell, with all required commands.
- Advanced Operations with Task Scheduler and Trigger Control Conditional triggers, event-driven execution, and PowerShell integration for reliable Windows Task Scheduler automation.
- Windows Server Time Synchronization and NTP Configuration A practical guide to time synchronization in Active Directory domains, covering PDC Emulator design, the w32time service, and GPO configuration using PowerShell.
- NIC Teaming Configuration and Redundancy Design Explains how to configure NIC Teaming in Windows Server using LBFO and Switch Independent mode, including dynamic load balancing, failover testing, and operational design.
- Windows Server Network Configuration How to configure NICs, DNS, and routing priorities on Windows Server using PowerShell, with best practices for multi-adapter environments.
- Complete Guide to Bash Special Syntax, Variables, and Expansions A complete reference covering all Bash special syntax, variables, expansion rules, and control structures with examples.
- How to Configure Proxy Settings on Windows A complete guide to configuring proxy settings for Windows users and system services, including WinHTTP and BITS.