On 2018/07/06 22:30 , Rami Al-Dalky wrote:
I have a question about using the probe's list of resolvers when creating a DNS measurement. It is unclear to me whether the probe would send the query to all resolvers at the same time or not! Also, does the probe send the query to all resolvers in its list or to a subset of those resolvers? Is DNS eyeball implemented in the probes?
Hi, The Atlas DNS measurement code sends one request at a time, in the order in which the DNS resolvers are listed in /etc/resolv.conf on the probe. In addition to measuring DNS, probe can also resolve a DNS name for the target of a measurement. In that case, the stub resolver that is built into libevent is used. That stub resolver does some clever and funky stuff. I don't know the details of how DNS queries are scheduled. Philip