Practical security guides for Linux sysadmins
Why mail, DNS and websites belong on servers you own, and how to put Cloudflare DNS, proxy, Tunnel, Access, Pages and R2 in front of them without giving up control. Includes the real-client-IP setup that most proxied servers get wrong.
Misconfigured SSL costs more than a certificate renewal. Learn how to check certificates, cipher suites, HSTS, and OCSP stapling from the command line — and how to automate the entire audit.
The 5 iptables mistakes everyone makes, common rule sets nobody memorizes, and a visual builder that generates correct rules for you. Includes iptables-to-nftables conversion.
Kill malware connections before they start. Set up BIND9 with Response Policy Zones, automated threat feeds from abuse.ch, Hagezi, and OISD, plus whitelist management.