About Paul Ispas
CTO, Linux Sysadmin and Infrastructure Engineer
I am Paul Ispas, known online as rojackal. I work as Chief Technical Officer at HPRO Group Limited, where I focus on Linux infrastructure, proxy and VPN systems, web performance, WHMCS automation, security, and production operations.
My background is hands-on. I work directly with servers, code, databases, networks, customer systems, billing platforms, and the kind of production problems that need clear decisions and fast, reliable fixes.
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Who I Am
Practical technical leadership built on real infrastructure work
I am not only interested in how systems look on paper. I care about how they behave in production, under load, when customers depend on them, when something breaks, and when the fix needs to be correct the first time.
Over the years, I have worked with Linux servers, NGINX, MySQL and MariaDB, PHP, WHMCS, proxy networks, VPN services, DNS, firewalls, certificates, automation scripts, monitoring, SEO infrastructure, analytics, and payment systems.
My approach is direct: understand the problem, remove unnecessary complexity, fix the root cause, document what matters, and keep systems stable.
Professional Focus
What I work on
Linux Infrastructure
Administration and troubleshooting of production Linux servers, services, logs, permissions, package builds, systemd units, backups, and long-term maintenance.
Web Performance
NGINX, PHP-FPM, FastCGI caching, Cloudflare handling, Brotli, HTTP/2, HTTP/3, SSL/TLS, WordPress optimization, and practical performance tuning.
Proxy & VPN Systems
HTTP proxies, SOCKS5 proxies, dedicated IP services, VPN infrastructure, IP allocation, authentication, abuse control, subnet management, and service reliability.
WHMCS & Automation
WHMCS modules, hooks, provisioning logic, billing automation, payment integrations, customer portal improvements, and backend operational tooling.
Security & Operations
Firewall rules, nftables, mTLS, certificates, access restrictions, abuse prevention, monitoring, incident analysis, and production hardening.
Technical Business Work
SEO, analytics, conversion tracking, advertising systems, technical marketing, product infrastructure, and the business side of running online services.
Current Role
Chief Technical Officer at HPRO Group Limited
At HPRO Group Limited, I work on the technical foundation behind proxy, VPN, billing, automation, customer-facing systems, server infrastructure, and web operations.
The work involves both planning and hands-on implementation. That means improving systems, solving production issues, reviewing code and configurations, maintaining infrastructure, reducing failures, and making sure the business can run reliably.
Areas I regularly deal with
- Linux servers and service operations
- NGINX and PHP-FPM stacks
- MySQL and MariaDB databases
- WHMCS billing and provisioning
- Proxy and VPN infrastructure
- Firewalls and access control
- Cloudflare, DNS and SSL/TLS
- Monitoring, logs and troubleshooting
My Working Style
Simple, stable and maintainable systems
I prefer proven solutions over fashionable complexity. A system should be easy to understand, easy to monitor, easy to repair, and hard to break. Good infrastructure is not only about using new tools. It is about discipline, clear ownership, proper logging, safe changes, and knowing what to do when things go wrong.
Technical Skills
Skills and technologies
Systems
- Linux administration
- Rocky Linux / RHEL-based environments
- Systemd
- Bash scripting
- RPM builds
- Server maintenance
Web Stack
- NGINX
- PHP-FPM
- WordPress
- WHMCS
- FastCGI cache
- Cloudflare
Databases
- MySQL
- MariaDB
- Query troubleshooting
- Operational maintenance
- Data exports
- Billing data workflows
Networking
- HTTP proxies
- SOCKS5 proxies
- VPN systems
- DNS
- SSL/TLS
- Firewall rules
Why This Website Exists
A personal place for technical notes and experience
I created rojackal.me as a personal website where I can publish technical notes, lessons learned, practical guides, and opinions from real infrastructure work.
The topics here will mostly be about Linux, servers, NGINX, MySQL, WHMCS, proxies, VPN systems, security, automation, SEO, and technical business operations.
The goal is simple: useful information, direct writing, and practical examples.
Contact
Want to connect?
You can follow my work through this website or connect with me through my public professional profiles.