#Firewall
Egress Firewall Breaks Domain Checks — Tests as root Pass
The domain order page reported every name as unavailable, even names I made up. The cause was an outbound DROP policy with port 43 missing from the allowed port list after an operating system migration. The trap was that tests as root passed every time. Testing must use the account that actually runs the app.
Managing Site Switches Remotely with UniFi's Cloud Connector Proxy
My workstation is in a different location from the site, with no VPN and no inbound ports open, but I still need to change VLANs per port, reserve fixed IPs, and track down failing cables. This article explains how Site Manager's connector proxy reaches the legacy API for both reads and writes without requesting a CSRF token, and the discipline needed when holding a key this powerful.
My Firewall Permanently Banned Googlebot and Hid Sites from Search
I investigated why sites disappeared from search results and found Googlebot in my own firewall's permanent ban list. 408 of 500 entries came from the counter tallying WAF false positives. How I lifted the bans, wrote a script to fetch official bot IP ranges into the ignore list daily, and dealt with a grep trap and the side effects of blocking entire countries.
Read-only Debian shared-host security audit — avoid banning yourself
Audit the security of a Debian server running DirectAdmin in read-only mode first — but the first trap is that scan traffic itself triggers CSF's brute-force rules and gets your own IP banned. This article lays out a safe audit sequence + areas to check in 2024-2026
libmodsecurity3 + nginx — only ctl:ruleEngine exclusions work
ModSecurity v3 (libmodsecurity3) + nginx + OWASP CRS — the ctl:ruleRemoveById taught in the guides does nothing and fails silently. This article covers what I found after trying every approach: ctl:ruleEngine works, scoped with a Host+URI chained rule, and the exclusion file must load before CRS.
Mail Checks Ban the Whole Office—Fixing It with Login Auto-Whitelist
Real mail clients behave exactly like bots — office machines keep retrying old passwords until CSF bans the whole office. This article covers an auto-whitelist system that watches for successful logins + Thai GeoIP, then grants a temporary allow for 24 hours, along with 5 pitfalls I learned the hard way.
LAN Access for a Team of 7 Without Open Ports: Cloudflare Zero Trust
A team of 7 needs RDP access to machines on the LAN without opening any ports to the internet — the Cloudflare Zero Trust architecture (WARP + cloudflared), with 3 lessons from implementation: a forgotten IdP setup, Gateway defaults that allow everything, and the default-deny rule people forget most often
Auto-Unblock the Office in CSF with a Geo+Account Gate
A real case of a client office whose IP changes daily, with a ghost device using an old password that repeatedly gets the whole office blocked by CSF. How I automated unblocking with a narrow account+geo gate that lets the real office through while keeping foreign credential attacks blocked.
Tuning ModSecurity on DirectAdmin for Shared Hosting
The 4 additions I made beyond DA defaults — exclusions before CRS, a 1-hit credscan ban, a fix for the incorrect MODSEC_LOG path shipped by DA, and a self-heal cron to recover from rebuild overwrites
DA Migration Finale — Security Fixes and Hardening After Stabilizing
Wrapping up the cross-distro DirectAdmin migration series with security work after the server stabilized — sudoers wildcard CVE, OpenSSL SECLEVEL, ModSec exclusions before CRS, a csfpost drop-in, and 5 layers that survive DA updates
CSF Auto-Unblock for Ghost Devices Amid Botnet Brute Force
A real case on a DA shared host where a ghost device in an office got the entire office blocked by CSF every morning. I explain a 4-layer auto-unblock setup that distinguishes office devices from a botnet without accidentally unblocking attackers.