These are some of the basic network topologies I configured when preparing for the CCNA R&S 200-125 exam.
A black hole for Internet advertisements
Fully-replicated DNS and DHCP Server with ad-blocking powered by etcd
Technitium DNS Server
Fast, multithreaded, modular and extensible DHCP server written in Go
DHCPv6 and DHCPv4 packet library, client and server written in Go
A modern, scalable, robust DHCPv4 and DHCPv6 server, with database (MySQL, PostgreSQL), hooks, multi-threading, RADIUS, NETCONF, Kerberos and more.
Containerized version of ISC DHCP server based on latest Ubuntu LTS