In this episode of PING, Joao Damas from APNIC Labs explores the mechanics of the Labs measurement system. Commencing over a decade ago, with an "actionscript" (better known as flash) mechanism, backed by a static ISC Bind DNS configuration cycling through a namespace, the Labs advertising measurement system now samples over 15 million end users per day, using Javascript and a hand crafted DNS system which can synthesise DNS names on-the-fly and lead users to varying underlying Internet Protocol transport choices, packet sizes, DNS and DNSSEC parameters in general, along with a range of Internet Routing related experiments. Joao explains how the system works, and the mixture of technologies used to achieve the goals. There's almost no end to the variety of Internet behaviour which the system can measure, as long as it's capable of being teased out of the user in a javascript enabled advert backed by the DNS!