Constant DNS errors

By sethbest
Jun 28, 2012
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  1. I recently switched from Verizon Fios to Brighthouse Cable (time warner) internet as I was really not using all the bandwidth I was paying for before. Unfortunately I have had nothing but problems in the month since installation.

    After significant troubleshooting I have alleviated several of the internal network issues I had with the new modem, but am still having a DNS problem. Essentially at seemingly random intervals, or immediately if I open bittorrent, websites will not connect. I reset and renew and dns flush but nothing helps. Some programs will stay connected (skype, dropbox, etc) and some will not (games seem to suffer the same as the web browsing). Resetting the modem does not seem to help.

    The diagnostic report through windows troubleshooting says its a problem communicating with the DNS server.

    The router receives dynamic IP and DNS information, so I can't change anything there, but I put some free dns servers on this computer's list instead of finding them automatically. This did not help though. This leads me to believe this is some networking communications issue, not a problem with the DNS servers themselves.

    I disabled DHT in Bittorrent but the problems still occur, so I just have stopped using it. Oddly enough when I open it on another computer I can still browse the internet on this one, though the dns problems do become more frequent even when its open on another computer.

    To emphasize the point though: the problem occurs at seemingly random intervals regardless of what applications are running, I am only noting bittorrent since it seems to trigger the problem very quickly.

    From all of this it seems like there is a problem between the new modem and my network (its just two routers with dhcp disabled hooking up wired computers throughout the house).

    I would be very glad for someone elses input on the matter, hopefully its a simple setting, but could be a defective router or modem I suppose as well.

    Thanks in advance.
  2. jdillman1502

    jdillman1502 TechSpot Enthusiast Posts: 232

    Do you have the same problems is your pc is plugged directly into the modem?
  3. sethbest

    sethbest TechSpot Enthusiast Topic Starter Posts: 167

    I have not noticed the problem when directly connected, though the problem happens pretty randomly so I can't be sure. I guess I can plug in a laptop and try opening a bunch of bit-torrent connections to see if it happens that way. Will post back after I give that a try.

    I think that you are on the right track though, seems likely its some issue between the modem/router and my routers. If you have any suggestions on settings to change in the modem/router or the connecting router I'll give them a try.
  4. jdillman1502

    jdillman1502 TechSpot Enthusiast Posts: 232

    Any specific reason you are using your own router along with theirs?
  5. sethbest

    sethbest TechSpot Enthusiast Topic Starter Posts: 167

    Well I'm using one router and one hub along with their modem/router. This is because I only had one hub but have a box of routers, so I disable DHCP and just used a router as a hub. As for why I have different routers: I plug different devices in at different spots in the house so its easier to have multiple hubs than to run dozens of long wires from one room with a 15 port hub.
  6. jdillman1502

    jdillman1502 TechSpot Enthusiast Posts: 232

    Ok, just want to make sure I have this correct. Your internet connection comes in to the ISP modem/router (obviously), then from there all the network cables are plugged into either the hub (hopefully you actually mean switch) or the LAN ports of other routers. Or do you have the cable from the ISP device plugged into the WAN/Internet port of a router, then from there the rest of the cables plug into either the hub or LAN ports of other routers? Have you set a static IP address for the LAN of every router you use?
  7. sethbest

    sethbest TechSpot Enthusiast Topic Starter Posts: 167

    Brighthouse Modem/router is set to automatically find its dynamic IP and DNS info. It has DHCP server enabled. Several devices connect directly with it.

    One cable runs to the other side of the house and plugs into a port on an ethernet hub (says hub on it). This hub connects to several devices and one cable that runs to a numbered port on a d-link router.

    Even with modded firmware on routers I don't use the WAN port unless its plugging directly into a modem. The Router has its DHCP server disabled, and is assigned a separate IP range. I was worried about the separate range affecting devices plugged into it, but it did not and the DHCP server from the brighthouse modem assigned its IP range to all devices on the network.

    It's been a long time since I set up my own network, so I forgot the differences between hubs and switches. Googling it now I see I should probably just plug in another router in that spot. I had not considered it as the cause of the problem since I thought the problem started before I installed the hub there (used to just be a coupler there).


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