Operating systems: Linux (Debian, Kali, Ubuntu)
Web servers: LAMP (Apache) and LEMP (Nginx)
Cloud computing: Amazon AWS and Google cloud
Programming languages: PHP, MySQL, Python
Penetration testing: Vulnerability scanner and security tools
Systems security: Hardening, Anti-malware, Intrusion Detection & Prevention Systems, Web Application Firewall
Perimetral security: Firewall (appliance), Web Application Firewall (cloud), Content Delivery Networks