What's new

RT-N66U 3.0.0.4.260.21 and DNS stop working

  • SNBForums Code of Conduct

    SNBForums is a community for everyone, no matter what their level of experience.

    Please be tolerant and patient of others, especially newcomers. We are all here to share and learn!

    The rules are simple: Be patient, be nice, be helpful or be gone!

tmpzero

New Around Here
I installed the latest release a few days ago and on 3 times now the DNS service on the N66U stops.

If I use an external DNS all is fine but using the N66U as DNS for my internal client (assign by DHCP) i get a query refused

C:\>nslookup some-site.com
Server: UnKnown
Address: 192.168.0.1

*** UnKnown can't find some-site.com: Query refused

C:\>nslookup some-site.com 8.8.8.8
Server: google-public-dns-a.google.com
Address: 8.8.8.8

Non-authoritative answer:
Name: some-site.com
Addresses: 12.34.56.78


How can I check what might be wrong internally in the N66U?
 
Do you use any customized config files or user scripts?

Is your WAN interface configured to accept the DNS from your ISP, or do you provide your own DNS on that page?

Is 192.168.0.1 really your router's IP? (default is usually 192.168.1.1, unless you have changed it)
 
I did enable JFFS and are trying to get the LED on/off thingie to work, but that is about all and DNS is accepted from my ISP so no manual config for my LAN.

Usually a router reboot makes it work flawless for some time and then suddenly alla internal LAN DNS request are getting refused by the N66U

and yes, 192.168.0.1 is my router (my net default and the router just replaced my old D-Link gateway so I didn't want to change all other IP's..)
 
That is unusual. Try checking the System Log after it happens to see if there is any error message getting logged. Also go to the Sysinfo page (under Tools) and check the free RAM as well as the CPU Load to see if everything is still normal.
 
Hi,

Had something which might be related. On Optusnet Cable, Australia here.
By default Optusnet assigns their primary DNS server.

Sometimes that DNS server suddenly gets very slow, every few minutes.
I also found that sometimes I lose WAN (or more precisely DNS) when the WAN IP gets renewed.

I set the DNS in WAN interface to a local DNS server from optusnet which is less used, no issues since.

I wonder if somehow there is an issue if the router (got RT-N66U BTW) gets a WAN IP renew and the DNS server responds slow it gets a bit confused ?

Anecdotal, I admit.
 
Having a poorly working DNS can have all sort of negative effects in general, depending on what services are trying to achieve name resolutions. There isn't much on the router that does that, mostly DownloadMaster (if enabled) and the ntp client. It can also seriously affect your PC itself (which is more likely than the router IMHO).

Providing your own DNS is probably the best solution there. Look at the DNS servers of other Australian ISPs as alternative. If you can't find any reliable, then you can look at Google's (8.8.8.8) for instance, however they might be a tad far from you network-wise, which might impact your overall Internet experience.
 
well, I have no issues with my ISP DNS, I usually manually use does when the error occurs.

So when the ASUS makes a "request denied" I can always use the same DNS as my ISP have assigned on the ASUS WAN side so there is something internally in the ASUS that gets faulty..

The RAM level seems fine, about 185-190MB free..

I'll monitor the situation more
 
I installed the latest release a few days ago and on 3 times now the DNS service on the N66U stops.

If I use an external DNS all is fine but using the N66U as DNS for my internal client (assign by DHCP) i get a query refused

C:\>nslookup some-site.com
Server: UnKnown
Address: 192.168.0.1

*** UnKnown can't find some-site.com: Query refused

C:\>nslookup some-site.com 8.8.8.8
Server: google-public-dns-a.google.com
Address: 8.8.8.8

Non-authoritative answer:
Name: some-site.com
Addresses: 12.34.56.78


How can I check what might be wrong internally in the N66U?

I have the same issue aftet update. But i have resolved it after fill in LAN -> DHCP Server -> DNS Server 192.168.1.1 (or 8.8.8.8)
 
Can you check to confirm that dnsmasq is indeed running when you have the issue? Connect through telnet, and run the following:

ps w | grep dnsmasq

See if it returns dnsmasq amongst the list of running processes.

Also check on the System Log page for any error message related to dnsmasq.

Are you using a regular DHCP connection, or a dial-in method such as PPPoE or L2TP?
 
Can you check to confirm that dnsmasq is indeed running when you have the issue? Connect through telnet, and run the following:



See if it returns dnsmasq amongst the list of running processes.

Also check on the System Log page for any error message related to dnsmasq.

Are you using a regular DHCP connection, or a dial-in method such as PPPoE or L2TP?

I reset DNS Server field in WEB-interface and click apply. After reboot my router working fine. Looks like the issue happens after firmware update and gone after modifying DNS Server field.

I using static ip connection.
 
Could have been a left-over from an older config possibly. Asus did quite a few changes surrounding dnsmasq and dhcp with build 220.
 

Similar threads

Latest threads

Sign Up For SNBForums Daily Digest

Get an update of what's new every day delivered to your mailbox. Sign up here!
Top