Security

The blog you’re reading just moved house. Same content, same build, the same Cloudflare Pages underneath — but the address on the door changed from billalrehmani.pages.dev to a domain that’s actually mine: billsblog.dev. Why bother — it already worked billalrehmani.pages.dev was fine. It served over HTTPS, it was fast, it was free. But pages.dev is Cloudflare’s namespace, not mine. For a portfolio I link from LinkedIn and want people to remember, “billalrehmani-dot-pages-dot-dev” is a mouthful and a borrowed address. Owning the domain means owning the identity — and, as it turned out, a bit more control over the security posture too. ...

A flat network trusts every device on it equally. A smart plug, a guest’s phone, and the machine holding my important data all share one space — so if any one of them is compromised, the attacker can reach the rest. Network segmentation breaks that flat space into separate zones and controls what may cross between them, shrinking the blast radius of any single compromise. I wanted to build that properly — VLANs and a firewall — on VMware Workstation with pfSense CE, and design three zones at deliberately different trust levels: ...

My lab is deliberately isolated — an automation VM (CLAUDDEB) sits behind a virtual pfSense firewall on a segment (10.10.0.0/24) that my home network can’t reach. That isolation is great until you’re out of the house and want to check your Grafana dashboards, which only listen inside that segment. I already use Tailscale for casual remote access, and I’ll be honest up front: for pure convenience, Tailscale wins — it punches through NAT automatically with zero firewall work. But this project wasn’t about convenience. It was about building the thing Tailscale is made of. Tailscale is WireGuard under the hood; hand-rolling raw WireGuard on pfSense teaches you how VPNs actually work — keys, peers, routing, firewall rules, NAT — at a level the managed tool deliberately hides. So I built it from scratch, kept Tailscale as my daily driver, and got a genuinely brutal debugging lesson in the process. ...

My Debian automation VM already sits behind a pfSense firewall with egress containment — it can reach the internet but not my home network. So why harden the VM itself? Because “behind a firewall” is doing less work than it sounds. Two paths reach into the VM without ever crossing pfSense, and an honest audit of my own box turned up drift I didn’t expect. This is the write-up: what the audit found, what I changed, and the systemd sandbox mistake that quietly broke a service. ...

I run my Claude Code work inside a Debian 13 VM (CLAUDDEB) on VMware Workstation Pro 17.6.4, with a pfSense 2.8.1 VM in front of it as a virtual router and firewall. pfSense exists in this setup for containment: if something on the Debian VM misbehaves — a prompt injection, a compromised dependency — it must not be able to reach my PC, my router’s admin page, or anything else on the home network. ...

This is a small home network — one router, a handful of devices. The point wasn’t complexity; it was applying the same discipline you would to a small office or lab environment. Treated that way, it doubles as practical study for Network+ and Security+. The router is an Arcadyan HWG2025 — the NBN-issued unit, Wi-Fi 7 with MLO, around 500 Mb down. An ISP router doesn’t give you much room to move, but it gives you enough to do this properly. ...