R8500 DNS periodic DNS errors/failures

Here's what happened with both of my issues regarding the Frontier F2250 bonded dsl modem feeding the R8500 router. One issue was the periodic DNS errors that started this thread and the other issue was in a separate thread regarding my downstream bandwidth getting halved by the R8500. In one fell swoop, both were resolved to my delight. 

A little background to set the table; The Frontier bonded modem's wireless-N radio would cause the modem to overheat and reboot a couple times a day. It was due to the ever-increasing # wireless toys that we purchased. They overwhelmed it's little ass. This in mind, I got an R8500 for the 802.11ac protocol that our newer phones, tablets, and devices were built on. Frontier modem went into transparent bridge mode and I leaned on the R8500 for all the workload. DNS errors, dropped connections, etc. These ended up being worse than the periodic reboot the Frontier modem would do. Top it off with the R8500 cutting my 20x1 service to 10x1.

For giggles, I disconnected the R8500 and shut it down. I reset the Frontier modem and provisioned it with the PPPoE settings favored by Frontier. I disabled my laptop's wireless and plugged into the modem via ethernet. I tested bandwidth three times over half an hour using Speedtest.net. I got 20Mbps x 1.1Mbps with 31ms pings each time. Reversing the setup by disabling the ethernet port on my laptop and enabling the wifi connection I tested three more times in half hour. I got 18Mbps x 1.1Mbps with 32ms pings. After this I disabled the Frontier modem's wireless radio.

A factory reset of the R8500 router later and I plugged one of the modem's LAN ports into the R8500's WAN port. I moved the ethernet cable I had used to plug into the Frontier modem for the speedtest into one of the R8500's LAN ports. During initial setup, the R8500 suggested a scenario whereby I leave the Frontier modem's wireless radio off and only have the R8500 plugged into the Frontier modem via ethernet. Anything downstream of the Frontier modem and the R8500 should only get connected to the R8500. Since the R8500 and the Frontier have different default IP addresses, there shouldnt be any issues between the two by way of DHCP servers being active on both devices. I ran the same speedtests in sets of three with wired and wireless connections to the R8500. Boom! I got 20Mbps x 1.1Mbps with 32ms to 34ms pings in both wired and wireless scenarios. Finally I ran the QoS speedtest inside the R8500 and it saw the full 20Mbps x 1.1Mbps that I should have been getting all along. For some damn reason, putting the Frontier in bridge mode confused the R8500 and it only pulled bandwidth from one of the bonded pair. Probably not compatible with ADSL2+ bonded modems. Too many addresses that the Frontier used to handle deftly when it was king of the hill were left in a pile for the R8500 when the Frontier was bridged. Anyway, things seem to have worked out. 

Thanks to those that tried to help and I'll go on doing what I do best; Being an example of what not to do. I have this running joke that I tell people when **bleep** like this happens to me. "There are two ways to do things, the right way and the wrong way. My way is a lot like the wrong way, but faster..."

-Mike