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D7000 DNS lookup die (appears as internet down)

walaj
Guide

D7000 DNS lookup die (appears as internet down)

As per others, I'm regretting buying this router/modem, but thats by the by. 

 

On an increasingly regular basis, my D7000 (v1, 1.0.1.68) 'looses Internet connection' - access to web sites fails, to the point where nothing appears to have access, despite the D7000 appearing fine, with no errors in (the exceptionally limited) log file. Phones tell me wifi is up, but there is no internet access. PC on ethernet still works for some stuff, but it gradually dies.

 

Fix is to reboot the modem. Which is a pain, and low on WAF.

 

It failed again this morning. Having some time to investigate, it appears that DNS forwarding has died.

 

as posted on another post here, I have the D7000 set up to provide DHCP allocation, which includes the DNS server details. These are actually set (on the D7000) to an internal dnsmasq server and as a backup, my ISP. 

 

When 'the internet fails', nslookup times out. Forcing nslookup to use the local box works fine. And in fact, once I switched the testdevice (macbook) to use the local DNS direct rather than the DHCP offered D7000, it was as if there was no problem.

 

SO - it seems the DNS forwarder on the D7000 is falling over.

 

A) anyway to check it directly on the D7000? EG which process should I be checking via telnet and is there any logging?

B) anyway to force the D7000 DHCP to offer the local server as DNS rather than itself? I can edit the config, but it gets overwritten on reboot.

 

According to https://github.com/negan07/ancistrus/wiki/Service-Inhibitions - dnrd is the forwarder - and is always used if DHCP is enabled.  I dont really want to move DHCP to another box, but suspect this is the fix...

 

 

* has anyone considered the 'improved' firmware at https://github.com/negan07/ancistrus ?

 

 

Model: D7000v1|Nighthawk AC1900 VDSL/ADSL Modem Router
Message 1 of 8
PickAuserName
Aspirant

Re: D7000 DNS lookup die (appears as internet down)

I have a similar issue with my R7000 (firmware v1.0.9.42_10.22.44) that started several weeks ago.

 

I assumed it was Comcast / Xfinity crappy DNS so I pointed at Google's DNS servers but the problem persists.  When DNS lookups fail the error comes back instantly.  From a time perspectrive there's no indication that the request actually went out to the internet, talked to some resolvers and came back.  It's just too quick.

 

I didn't take my troubleshooting as far as you did but my gut tells me something is broke on the router itself.

Message 2 of 8
walaj
Guide

Re: D7000 DNS lookup die (appears as internet down)

In my D7000 case, DNS lookups from a DHCP served client start to timeout. Changing the DNS resolution on that device to avoid the router and either go direct to my local box or an external server instantly fixes it

Message 3 of 8
PickAuserName
Aspirant

Re: D7000 DNS lookup die (appears as internet down)

When I changed my DNS settings I changed them on the router itself (not the PC).

 

That is a good idea.  I have changed my PC settings to point to Google's DNS and bypass the router.  I'll report back and see how it goes.

Message 4 of 8
walaj
Guide

Re: D7000 DNS lookup die (appears as internet down)

@PickAuserName - did you get anywhere with checking - interested to know if this is just me, or wider...

Message 5 of 8
PickAuserName
Aspirant

Re: D7000 DNS lookup die (appears as internet down)

hello @walaj 

 

I set my PC to use 8.8.8.8 and 8.8.4.4 and have seen zero DNS issues since the change.

Message 6 of 8
walaj
Guide

Re: D7000 DNS lookup die (appears as internet down)

Which tends to suggest you had the same issue. 

 

And that dnrd on the D7000 crashes/locks up/fails for some reason. The fix to which is either not use it (hardware DNS server into each machine), or put up with rebooting the D7000 regularly.

 

 

Message 7 of 8
walaj
Guide

Re: D7000 DNS lookup die (appears as internet down)

as an update - the comment from telnet to restart the stalled dns forwarder:

 

rc dnrd restart

 

resolves my problem everytime. 

 

Im slowing moving over to the enhanced firmware at https://github.com/negan07/ancistrus/

 

 

Message 8 of 8
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