Re: people use windows server's DHCP ?
Basic infrastructure rule #3. Do not use Windows for any critical infrastructure*. Use Linux, BSD, or an appliance - which will be running Linux.
Wave dozens of specialized devices the computer room down the hall - proxies, filters, DNS, DHCP, firewall, load balancers from a couple of firms, core network switches, intrusion prevention, network monitoring, IP management, high speed decrypt/encrypt, more monitoring, anti-malware, more anti-malware, patch systems, backup systems, phone systems, network management, more patch management, access control, VPN, NTP, more VPN, and so on... from at least a score of vendors. Every single one of them, under the hood, is a Linux box. It is efficient, reliable, stable, and relatively secure... which is why every vendor uses it to build critical infrastructure. That's a hint for those of us who run the networks and data centers.
* maybe, if you are still using Windows heavily, AD.... but don't let AD do your DNS with Microsoft DNS - make it talk to a non-Windows DNS server.