DNS

It’s always DNS:

• MaraDNS, a lightweight DNS server that uses Lua for scripting replies.
• Bruno’s node, from where the above image (which he rightly entitled “DNS for dummies”) was pilfered. It is invaluable in explaining to clueless Marketing people how things actually work.
• djbdns Record Builder
• pdnsd, for pacifying DNS-intensive applications over unreliable links.