Nazmul Ahsan

Data analyst

May 2025 - Present • 1 yr 2 mos

Freelance Data Analyst with hands-on experience in SQL, MySQL and Power BI dashboard development. Achievements: - Built microfinance dashboard analyzing 700 borrowers and 67M taka loan portfolio across 8 divisions using MySQL and Power BI - Built e-commerce sales dashboard analyzing 10,000+ transactions across 4 regions using Power BI with DAX measures and KPI tracking - Cleaned and validated real world data using SQL — NULL handling, duplicate removal and data quality checks in MySQL Workbench I help clients turn raw data into clear visual dashboards and business insights for faster and smarter decisions.

Senior System Engineer(Cloud Operation)

Apr 2019 - Present • 7 yrs 3 mos

Analyzed business and technical requirements and translated them into secure, scalable system and infrastructure solutions. Designed system architecture encompassing cloud infrastructure, server environments, network topology, and database systems. Implemented and maintained Linux and cloud-based servers, including server hardening, security controls, patch management, and performance tuning and also PHP script. Security Hardening & Threat Protection (SSH Hardening, Fail2Ban, CrowdSec, ModSecurity WAF, XDP, TCP SYN Cookies, Kernel Hardening, SSL/TLS Hardening, AppArmor/SELinux, ClamAV, Two-Factor Authentication, Wazuh/OSSEC, Tripwire, DDoS Protection, Rate Limiting, GeoIP Blocking, Nginx/Apache Hardening, PHP Hardening,Docker Security, Log Monitoring, Malware Scanner, Web Shell Detection, Brute Force Protection and others) Firewall & Access Control (iptables, nftables, UFW, CSF, firewalld, Cloudflare, WireGuard VPN, OpenVPN, GeoIP Blocking, Port Knocking, HAProxy ACL,Reverse Proxy Filtering, Zero Trust , Cloud Provider Firewall, AWS Security Groups, Google Cloud Firewall, Nginx Access Control, Apache Access ControlP, Whitelisting, IP Blacklisting and others) Evaluated existing systems to identify performance bottlenecks, security vulnerabilities, and availability risks, and implemented corrective and preventive actions. Configured and optimized network infrastructure to improve reliability, throughput, and service availability. Administered database systems, ensuring data integrity, backup, recovery, and operational compliance. Monitored system health and performance, ensuring high availability and operational continuity. Diagnosed and resolved system, hosting, and infrastructure-level issues, minimizing downtime. Prepared system documentation, architecture diagrams, technical reports, and operational guidelines. Completed secure system deployment, delivery, and formal handover to global clients, including knowledge transfer and post-deployment support coordination.