osx v10.11.6 (El Capitan)
Our local network is ethernet, 1Gb capable. The Internet connection is 10 Mb/sec.
At random and rare intervals, the network throughput of the iMac drops to a few KB /sec. There is no predicting when it happens. The slowdown lasts from 15 min to on hour; then all is well again.
During the slowdown, data transfer is very slow (1 - 10 Kbit/sec), and unreliable. Connections are frequently dropped or restarted.
I succeeded in tracking some of the traffic during the most recent occurrence. The issue appears to be a, um, "disbelief" by the system of the results of a DNS request. So the name resolution is made over and over.
Does this sound familiar to any one? If so, is there a solution?
