$ cat ~/about.md
About me
My name is Sotiris Roussis, also known as xtonousou /ˈex to ˈnu su/.
I'm an IT professional with a broad and deep understanding of modern technology stacks. My journey started with tinkering on Linux systems and has evolved into a career that spans systems engineering, network architecture, software development, and cybersecurity.
Beyond tech, I'm a gamer at heart. I appreciate art in various forms, collect life quotes that resonate, and believe in documenting not just technical knowledge, but personal experiences and reflections that make us human.
When I'm not working or gaming, you'll find me in my homelab experimenting with new technologies, creating guides, writing about lessons learned, or simply sharing thoughts on life, listening to music, sharing news and random observations.
$ cat ~/expertise.json | jq '.'
Systems Administration
Deep expertise in Linux and Windows Server environments. Experienced with virtualization platforms (VMware, Proxmox, KVM), storage solutions, backup strategies, and high-availability clusters. Comfortable managing fleets of bare-metal and virtual machines at scale. Proficient with reverse proxies (Nginx, Caddy, Traefik, HAProxy, Varnish) and mail server infrastructure (Postfix, Dovecot, MS Exchange).
Network Engineering
Solid foundation in TCP/IP, routing protocols (BGP, OSPF, OpenFabric), switching, VLANs, VRFs, and network segmentation. Hands-on with firewalls (pfSense, iptables, commercial appliances), VPNs (WireGuard, OpenVPN, IPSec), and load balancers. Experienced with cloud networking at scale using Azure Virtual Networks, AWS VPC, Transit Gateways, and software-defined networking. Implements zero trust networking architectures and zero trust application access models.
Software Development
Full-stack developer proficient in Python (FastAPI, Django, Flask), TypeScript/JavaScript (Express.js, Bun.js, React, Vite, Astro), and Bash. Builds CLI tools, REST APIs, automation scripts, and modern web applications. Experienced with relational databases (MySQL, PostgreSQL, MSSQL) and time-series databases (InfluxDB, TimescaleDB, ClickHouse). Follows clean code principles, writes tests, and believes in pragmatic engineering.
Cybersecurity
Experienced in offensive and defensive security. Performs penetration testing, vulnerability assessments, and security audits. Familiar with SIEM platforms, IDS/IPS, incident response procedures, and compliance frameworks. Specializes in modern encryption standards and post-quantum safe (PQS) cryptography for future-proof security implementations.
DevOps & Cloud
Expert in Azure and AWS cloud platforms, as well as on-premises cloud infrastructure. Containers everywhere — Docker and Kubernetes in production. Builds CI/CD pipelines across GitHub Actions, GitLab CI, and Gitea Runners. Manages infrastructure as code with Ansible and Terraform. Monitoring and observability with Zabbix, Nagios, Elastic Stack, Prometheus, Grafana, Promtail, and rsyslog. Practices GitOps for deployment automation.
Architecture & Design
Designs resilient, scalable system architectures. Creates comprehensive network topologies, infrastructure diagrams, and technical documentation. Bridges the gap between engineering requirements and business objectives.