Hello, I have xfinity service with a Netgear CM1150V cable modem connected to a Netgear FVS338 router. It seems that on a weekly and recently nightly basis, I will loose DNS service for a period of 10-20 minutes. Sometimes rebooting the router seems to fix the issue. I understand that the message of a loss of DNS services may be due to another issue, so I will post the diagnostics from the modem. I seem to get this error regardless of what DNS service I use. Any suggestions would be helpful. Oh, the cable modem is connected to the coax outlet in the house, there are also two TVs in the home that are coax connected.
The upstream power is too high and it may be intermittently fluctuating even farther out of spec. The downstream power is on the weak side as well. That can cause random disconnects, spontaneous re-booting of the modem, speed, packet loss, latency problems, and the un-bonding of channels.
In a self troubleshooting effort to try to obtain better connectivity / more wiggle room, check to see if there are there any excess/unneeded coax cable splitters in the line leading to the modem that can be eliminated/re-configured. Any splitters that remain should be high quality and cable rated for 5-1002 MHz, bi-directional, and no gold colored garbage types like GE, RadioShack, RCA, Philips, Leviton, Magnavox, and Rocketfish from big box stores like Home Depot, Lowes, Target, Wal-Mart etc. Splitters should be swapped with known to be good / new ones to test
If there aren't any unneeded splitters that can be eliminated and if your coax wiring setup can't be reconfigured so that there is a single two way splitter connected directly off of the drop from the street/pole with one port feeding the modem and the other port feeding the rest of the house/equipment with additional splits as needed, and you've checked all the wiring and fittings for integrity and tightness and refresh them by taking them apart then check for and clean off any corrosion / oxidation on the center wire and put them back together again, then perhaps it's best to book a tech visit to investigate and correct.