A four-VM Windows Server 2025 setup in VirtualBox that simulates a small business network. There's a domain controller running AD DS, DNS, and DHCP, a routing server handling NAT, a file server with role-based SMB shares, and a domain-joined Windows 11 client. OUs, security groups, and Group Policy handle things like drive mapping and Control Panel restrictions, the same way you'd set it up in a real small business.
My first LAN topology, built in Cisco Packet Tracer. Three VLANs (Office, Warehouse, Servers) and a management VLAN, two access switches uplinked to a core switch, a router, and a simulated ISP.
A Raspberry Pi running Debian 13 and Docker Compose as a small home server. It runs Pi-hole for DNS filtering on selected devices, Jellyfin for media streaming, and a Homepage dashboard. The media library lives on a Windows desktop and is mounted over SMB with a systemd automount, so the Pi's boot doesn't depend on that machine being online.
A Raspberry Pi running Debian and Docker that watches over the home lab. It uses Uptime Kuma to monitor eight systems and services, everything from internet connectivity and DNS resolution to the domain controller and file server. It reaches the isolated VirtualBox network through a static route on the lab's RRAS server, and it's already caught and logged a real outage during testing.