The classical approach for Internet topology measurement consists in collecting as much data as possible and in constructing from it a view of the topology by merging the obtained data. Although this approach may seem reasonable, in most cases network measurements give partial views of the networks under concern, contain erroneous data, and may moreover be intrinsically biased. Here we present a new tool, namely UDP PING, that relies on a very different approach for the measurement of the Internet topology. We show the principles on which it relies and how to use it to deploy real worldwide measurements for obtaining a reliable estimation of the real degree distribution of routers in the core Internet.