[Help] Constant DNS lookup failures

Blorgon

Limp Gawd
Joined
Jun 29, 2014
Messages
363
A few weeks ago, I started getting intermittent DNS lookup failures. I looked into it, and everything I found suggested switching to Google's public DNS.

So I switched to that in my router's settings, but I still had problems, albeit a little less frequently. Eventually I got fed up and forced my ethernet adapter's settings to default to those addresses too, in case my router wasn't pushing them to my computer for whatever reason.

Even after that, and several flushes, I'm still getting DNS lookup failures at least once an hour. It's driving me absolutely nuts. Sometimes, I'll open up my ethernet adapter options in the control panel, and as soon as I do, the internet comes back on.

Any ideas? Something on my end? Switch to OpenDNS?

  • TP-LINK Archer C7 router

  • ARRIS SURFboard SB6141 modem

  • ~180 down, ~15 up (testmy.net)

  • Desktop directly connected to router via ethernet
 

mayhem87

Limp Gawd
Joined
Oct 21, 2008
Messages
358
are you sure its DNS and not Inet as well? How long does it last for? Can you verify Inet connectivity by pinging a public IP instead of DNS name? Is it only that computer?

Honestly packets drop and its just something that happens. I wouldn't normally recommend connecting directly to the modem however, you could try that and get packet captures of the dns requests going out to see if they ever come back.

You could try tracert and seeing if you find anything strange with the hops to the DNS server. Once it leaves your modem though GL getting help with it so I suggest you try as much as possible on your end. If you frequent certain sites maybe add those to your hosts file or put back your router as the DNS server and have it cache DNS queries for frequent sites.
 

Blorgon

Limp Gawd
Joined
Jun 29, 2014
Messages
363
Did you try disbling the DNS Client service?

I haven't tried that, no. I looked it up though, and I found a lot of people saying not to do that, ever. What do you think it will solve?

are you sure its DNS and not Inet as well? How long does it last for? Can you verify Inet connectivity by pinging a public IP instead of DNS name? Is it only that computer?

Honestly packets drop and its just something that happens. I wouldn't normally recommend connecting directly to the modem however, you could try that and get packet captures of the dns requests going out to see if they ever come back.

You could try tracert and seeing if you find anything strange with the hops to the DNS server. Once it leaves your modem though GL getting help with it so I suggest you try as much as possible on your end. If you frequent certain sites maybe add those to your hosts file or put back your router as the DNS server and have it cache DNS queries for frequent sites.

Sometimes the DNS failures last a few minutes, and usually going into my adapter settings and disabling/re-enabling the ethernet adapter is enough to get it back up. Sometimes just opening the control panel seems to fix the problem (I'm sure it's just a coincidence of timing, although it's happened several times now).

Internet works fine on my phone through wifi when this happens, but my desktop is dead in the water. Maybe a faulty ethernet adapter? Faulty cable?

^^^ I was mistaken. I may have been on data when I tried my phone, or the internet may have switched back on by the point I was trying to load a webpage. Disregard the bit about my phone!

I updated my driver, but that didn't help, so it's not the driver.

Unfortunately, your suggestions all went a little over my head. I'm gonna have to figure out how to do all the stuff you recommended, so you might not hear from me for a while.
 
Last edited:

Vyedmic

Limp Gawd
Joined
Jul 20, 2007
Messages
222
I haven't tried that, no. I looked it up though, and I found a lot of people saying not to do that, ever. What do you think it will solve?

I had troubles with it before. Super long DNS lookups and even timeouts that were solved by disabling the local cache. You are saving mere bytes of network traffic by having it on.
 

mwarps

Supreme [H]ardness
Joined
Oct 6, 2002
Messages
7,059
Is IPv6 enabled? As much as everyone wants it to be ready, it still isn't. I get intermittent IPv6 lookups and connection attempts all the time.
 

ND40oz

[H]F Junkie
Joined
Jul 31, 2005
Messages
12,587
If it's localized to your desktop, then it's most likely not your other equipment (could still be the router though). What OS are you running and do you have a spare wireless adaptor usb/pcie adaptor you can drop in it to test with?
 

Blorgon

Limp Gawd
Joined
Jun 29, 2014
Messages
363
If it's localized to your desktop, then it's most likely not your other equipment (could still be the router though). What OS are you running and do you have a spare wireless adaptor usb/pcie adaptor you can drop in it to test with?

It's not localized to my desktop. I'm on Windows 10, and do not have spares.

Waiting for another DNS failure to do a tracert. Will report back.
 

ND40oz

[H]F Junkie
Joined
Jul 31, 2005
Messages
12,587
It's not localized to my desktop. I'm on Windows 10, and do not have spares.

Waiting for another DNS failure to do a tracert. Will report back.

If it's not localized to your desktop, what other systems or devices are you having this same problem on? You said your phone continued to work fine but your desktop is dead in the water but didn't mention any other devices or systems that are having the same issues as your desktop.

Internet works fine on my phone through wifi when this happens, but my desktop is dead in the water. Maybe a faulty ethernet adapter? Faulty cable?
 

Blorgon

Limp Gawd
Joined
Jun 29, 2014
Messages
363
If it's not localized to your desktop, what other systems or devices are you having this same problem on? You said your phone continued to work fine but your desktop is dead in the water but didn't mention any other devices or systems that are having the same issues as your desktop.

Whoops. I was mistaken. My phone does not work when this happens. Nor my Chromebook. My bad.

I will edit that post for clarification. Sorry again.
 

Blorgon

Limp Gawd
Joined
Jun 29, 2014
Messages
363
Have you updated the router to the latest firmware? Looks like there are 3 versions of it, so make sure you grab the correct one: Download for Archer C7 V1 - Welcome to TP-LINK

Hmm. Just tried. My C7 is actually a v2, so I went to that page instead. Alas, I'm getting an error when trying to install the .BIN:

d06710ea8d.png


And yes, I chose the correct firmware version.

¯\_(ツ)_/¯


EDIT: I guess this is a thing?
 

Blorgon

Limp Gawd
Joined
Jun 29, 2014
Messages
363
UPDATE: did a tracert during a DNS failure. Request timed out after first hop.
 
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