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Open Systems Server

Unix Administration // LAMP_Core

Linux / UnixBash AutomationLAMP StackiptablesQEMU / KVMsystemd

Overview

A deep dive into Unix and open-systems server administration, spanning the OS-Unix and Open Systems Servers courses. The work ranges from low-level command-line mastery and Bash automation to provisioning nested virtual machines, deploying a hardened LAMP stack, and architecting stateful firewalls with a default-deny security posture.

Major Projects

  1. 01

    Multi-OS Deployment & Interactive Systems Automation

    QEMU/KVMDebianUbuntu 22.04 LTSArch LinuxBashsystemd

    Overview // Architected a nested virtualization environment and developed a root-level automation script to streamline system reconnaissance and service monitoring.

    • Infrastructure Provisioning: Deployed and managed nested virtual machines (Ubuntu Minimal and Arch Linux) using QEMU/KVM and Virtual Machine Manager within a primary Debian host.
    • Environment Configuration: Transitioned minimal command-line server installations into fully functional environments by manually installing base packages and configuring the Cinnamon GUI desktop via apt.
    • Identity Management: Administered user provisioning, established home directories, and configured system permissions across multiple discrete operating systems.
    • Bash Automation: Engineered an interactive, root-level (sudo) Bash script utilizing advanced conditional logic (if/elif/else) to automate routine administrative queries.
    • Dynamic Data Parsing: Integrated grep and id commands to dynamically parse the /etc/passwd file, validating user existence and extracting specific user IDs on demand.
    • Service Monitoring: Programmed the script to query the live status of system daemons using systemctl list-units, incorporating robust error handling to manage queries for non-existent services gracefully.
    • Persistent Logging: Implemented advanced I/O redirection utilizing exec &> and the tee command to simultaneously stream execution output to the terminal display while persistently appending records to an administrative log file (sysinfo-output.txt).
  2. 02

    LAMP Stack Architecture & Stateful Firewall Engineering

    LinuxApacheMariaDBPHPiptablesWordPress

    Overview // Engineered a secure, highly available web infrastructure by building a LAMP stack from the ground up, protected by a custom stateful firewall architecture.

    • Network Security: Designed and deployed a strict default-deny firewall architecture using iptables, enforcing a baseline DROP policy on the INPUT chain to mitigate unauthorized access attempts.
    • Stateful Packet Inspection: Implemented connection tracking modules (-m state --state ESTABLISHED,RELATED) to dynamically permit returning traffic for active sessions while keeping unused ports heavily restricted.
    • Service-Specific Rulesets: Configured explicit firewall rule exceptions to allow critical inbound traffic for remote administration via SSH (TCP Port 22) and web traffic via HTTP (TCP Port 80).
    • Rule Persistence: Ensured network security configurations survived system reboots by deploying iptables-persistent and netfilter-persistent save utilities.
    • Web Infrastructure Deployment: Configured the Apache web server by structuring custom Virtual Host configuration files (.conf), defining Alias paths, and establishing directory-level access controls (e.g. AllowOverride Limit Options).
    • Database Hardening: Provisioned MariaDB and executed mysql_secure_installation protocols to remove test environments and secure the root database account.
    • Access Control & SQL: Formulated SQL commands to deploy a dedicated application database, created restricted service accounts, and applied the principle of least privilege by granting granular permissions (GRANT ALL PRIVILEGES).
    • Application Integration: Successfully integrated a complex PHP-based Content Management System (WordPress) by manually defining environment variables, database hosts, and secure credentials within core application configuration files.

Skills Gained

CLI Navigation & Environment Control

  • Mastered Unix filesystem traversal, environment variable management, and extended shell globbing (shopt -s extglob).

Advanced Text Processing & Data Pipelines

  • Built complex data extraction pipelines using sed, awk, grep, cut, sort -k, uniq, and tr.
  • Mastered POSIX Regular Expressions (RegEx) and complex I/O redirection (>, 2>&1, |, tee).

Process & Storage Management

  • Handled system processes via ps axu, top, and signal handling (SIGKILL).
  • Managed disk quotas and block usage (find, df, du).

Security & Permissions

  • Executed manual base conversions (Binary / Octal / Hex) to administer Access Control Lists (ACLs) via chmod.
  • Established default security masks using umask and managed root-level privilege escalation (IAM).

Nested Virtualization

  • Provisioned and managed nested VMs (Ubuntu 22.04 LTS, Arch Linux) using QEMU/KVM within a Debian host.
  • Configured GUI environments (Cinnamon) from minimal server installs.

Service Management

  • Utilized systemd and systemctl to initialize, enable, and verify the persistent states of critical system daemons across reboots.

LAMP Stack Administration

  • Deployed and administered Apache (apache2) with structured Virtual Host configurations.
  • Secured MariaDB / MySQL databases (mysql_secure_installation, granular GRANT privileges) and deployed PHP-based applications (WordPress).

Network Security

  • Engineered stateful packet inspection firewalls using iptables.
  • Enforced default-deny architectures (DROP policies) while explicitly permitting HTTP and SSH.
  • Ensured rule persistence via netfilter-persistent.
INTERACTIVE_TOOL // LIVE_DEMO

chmod Calculator

A live tool I built to make Unix permissions click. Toggle the rwx matrix and watch the octal, symbolic, and binary forms update in real time — or go the other way and type an octal value to decode it. It generates copy-ready chmod, chown, and umask commands for your distro. Everything runs locally in your browser.

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