DNS Stops working every hour or so (Not the server)

chris6273

chris6273

chris6273

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Hi guys,

For some reason recently my home network has been playing up. Every hour or so the DNS will conk out and stop working for around 3-5 minutes until it kicks back into life again. Data still transfers to the internet while this DNS issue is occuring.

I have tried using Open DNS Servers and my standard BT DNS Servers.

I can confirm it doesn't work because Chrome says "Sending Request" and when trying to ping bbc.co.uk it doesn't resolve.

Does anyone know where the issue may lie? Router or ISP?

My Server has issues at exactly the same time and uses different DNS servers. I've tried Open DNS Servers as well as my standard ISP Servers.

Any ideas? It's really annoying!

Thanks for your Help.
 
if u have 2 computers both with manual and different DNS, its ur webs. BT ur ISP ye? so u tried open DNS, BT's DNS, used googles? i wouldn't expect to make a difference (8.8.8.8) have you also tried (unsure if option available on BT's router) to ping a website from the ROUTER, at least if that fails you can point towards that, and drop your PC's out of the issue

but any existing connections to the internet remain during this process...but you cant browse yeah? i'd be running 2 constant ping tests, 1 on local network and 1 to a website, leave them, see if they drop during this, but have them running before the issue presents its self.
 
MilanoChris said:
So if you ping the IP it works?
Click to expand...

Yes, it keeps working throughout the problem.


richyrichuk said:
if u have 2 computers both with manual and different DNS, its ur webs. BT ur ISP ye? so u tried open DNS, BT's DNS, used googles? i wouldn't expect to make a difference (8.8.8.8) have you also tried (unsure if option available on BT's router) to ping a website from the ROUTER, at least if that fails you can point towards that, and drop your PC's out of the issue

but any existing connections to the internet remain during this process...but you cant browse yeah? i'd be running 2 constant ping tests, 1 on local network and 1 to a website, leave them, see if they drop during this, but have them running before the issue presents its self.
Click to expand...

BT is my DNS, yes. Yes I have and it fails from the router as-well.

None of the pings drop throughout the problem. This is mainly because DNS isn't required to ping an IP after the domain for it has initially been resolved.


Voodle said:
what router do you have?
Click to expand...

I have a Billion 7800N.

Any Ideas?
 
ah okay, check if it has any DoS defense options - on my draytek router there's a DoS UDP flood defense option, if it's enabled, regular DNS traffic can go over the threshold and be blocked unless the threshold is upped or that option is disabled.
 
if it fails from router, ISP issue.

get BT's network operations to look at it, the thing that'll be useful also IF u have a ori BT router, to put on to test the issue from there.

try usual from BT.....change P/w for ADSL login, get them to refresh IP, i can't remember if BT is dynamic or not...try again...but essentially that's BT issue not yours to resolve.

also i take it u can browse via IP during this time as its a DNS issue?
 
What I'd do..

Put latest firmware on there, reset the router to factory settings, setup with Google DNS servers.
 
I was experiencing something similar, it started happening when i switched to google chrome.

I have 3 DNS servers in my home network, the one on my netgear router, a BIND one i configured on a WHSv1 box and a windows 2012 one. For some reason after a number of hours id just stop being able to resolve anything from the PC, didnt matter which of the 3 DNS servers i tried, if i disabled/reenabled the NIC, or pulled and reconnected the cable. I could use a laptop also wired into the network to verify all 3 DNS servers were still working

I eventually narrowed it down to being due to chrome because it happened twice while using chrome on my ipad too. For me though it didn't come back after a period I simply had to reboot the machine/ipad and there were no logs in the eventlog to suggest why it had happened

I replaced the firmware on the router to see if it helped and that's now running DD-WRT but it didn't make any improvement. I eventually gave up troubleshooting in favour of upgrading to windows 8 (not because i wanted to, but im going to have to use it at some point to make sure i can support it hence forcing it on myself by installing on my main pc)
 
Well if it is chrome in his case too that is triggering this behaviour he can look into if there is some addon or chrome feature that is causing it and look for a workaround

Might be that chrome is doing some background dns verification in a way that is tripping up the DNS forwarder on the router, and after a period the router sees its not working and restarts it hence why he only has a 5 minute outage, whereas in my case it was clearly upsetting something in windows that didnt self correct and left me needing to reboot

Or it could be that the two things are unrelated and its nothing to do with chrome, but if he tries using firefox for an hour and it doesn't occur he'll be a little closer to diagnosing the problem, im only hinting that chrome could be a possible cause
 
ok fair doos, ye a Q is worth answering just like u said to narrow, even though a direct DNS lookup failed.

IP lookup and change of router before BT will issue a LL14 to the house, but thats a network issue that, need opps to look into it. but after IP and password change to refresh any stored info in the network (not local)
 
Sorry for the late reply guys, seems the email notification system on the forums is broken.

What I have done so far is put a HomeHub on the line and as soon as I put it on, the problems stopped. So it seems to be a fault with the 7800N I have.

It's nothing to do with Google Chrome because I can't resolve IPs on the router or my server.

I've tried to set up OpenDNS Servers on the router but it didn't make a difference. Seems to be the router not routing DNS requests.

Something weird is when the problem is occurring and I try to 'set vc' in nslookup, the DNS Requests can get through (Setting VC sets DNS Requests for nslookup to use TCP/IP instead of UDP).

When setting it back to 'set novc' (Back to UDP) queries don't get through until the router decides to kick back to life.

It isn't a problem with my line because the HomeHub works on it flawlessly (And is such an inferior router than the 7800N), so it seems UDP packets are not getting through for DNS.

Could it be a hardware fault? Because I've tried two different Firmware versions and both haven't worked when they used too?

Thanks for your help
 
Did you restore the router to factory settings after changing the firmware? Billion are pretty adamant that you should do this.
 
Suarez7 said:
Setup the DNS on the computer itself so it bypasses the DNS servers stored on the router.
Click to expand...

I've tried that but it didn't make any difference. Seems I forgot to add a list of things I've tried in my first post:

  • Changing DNS Servers both on my Computer & on my Routers' DHCP Server to OpenDNS Servers.
  • Doing a complete factory reset of my 7800n
  • Resolving a domain on my modem interface when the DNS problem occurs (Times out)
  • Resolving a domain name on my Server - Same problem
  • Leaving it a few days and trying again; this problem has been happening for over a week now


bledd. said:
Did you restore the router to factory settings after changing the firmware? Billion are pretty adamant that you should do this.
Click to expand...

Yes; I did it when specifying the firmware file on each reflash and I've tried it after flashing as-well on one occasion.

Any more ideas?
 
use wireshark on a PC to see what happens when you start getting no responses or use nslookup cos that'll do the same thing for seeing the DNS responses (though you won't see where they're going so well). what you've described sounds like a firmware level problem to me, have you contacted billion to see if they're aware of anything like that?
 
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