RCSII's profile

Frequent Visitor

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6 Messages

Wed, Jan 13, 2021 4:00 AM

DNS Issues - No DNS Responses

I continually have DNS issues with my Comcast service. It is not a WiFI issue becasuase:

1) We never lose the Wifi Connection

2) Windows and Browsers report DNS errors when this "outage" happens

3) My work VPN connection does not drop on my work laptop and I am still a able to to browse.

 

This happens multiple times a day, and allways the same issue. The DNS resolution is down for 2-3 muinutes at a time. 

 

How can I trouble shoot this on my end?

 

Thanks,

Rick

Responses

BruceW

Gold Problem Solver

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22.8K Messages

8 m ago

Devices often report a "DNS Error" when they are actually having trouble reaching the Internet at all. This is because when you click a link and as the page loads, the first thing the device needs to do is look up the IP address of the site, using DNS. Typically this needs to be repeated many times to load all of the page components. If any of these lookups fail because a of an Internet connection problem the device won't be able to access DNS and may incorrectly announce a "DNS Error" when "Lost Internet Connection" would be a more accurate message.

 

Are you connecting via Wifi or Ethernet? If Wifi, it's best to switch to an Ethernet cable connection if possible. That would allow you to determine whether the problem is with the Wifi signal, or with the link between your equipment and Comcast's network. Network connection problems that affect both Ethernet and Wifi devices are often due to poor coax connections, usually in or near your home.

If you want to troubleshoot this yourself, please see Internet Troubleshooting Tips. If you still need help, please post your Internet plan speed and the following information from your modem or gateway:

  • model number
  • downstream power levels and SNR
  • upstream power levels
  • event log

If you can't find the problem or you'd rather have Comcast take care of it, call them at the phone number on your bill or 1-800-Comcast, or use one of the options on https://www.xfinity.com/support/contact-us/. If they can't fix the problem remotely (unlikely), insist they send a tech out to identify the cause and correct it.

If the tech finds bad coax, splitters, amplifiers, or connections in your home (even if Comcast originally supplied them) you'll probably have to pay for the visit unless you have their Service Protection Plan (https://www.xfinity.com/support/articles/service-protection-plan, closed to customers that don't already have it). If the trouble is due to a faulty Comcast rental device, or anything outside your home, you shouldn't be charged.

 

Frequent Visitor

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6 Messages

8 m ago

Hey Bruce, 

 

I wil take a look at the links that you sent. It is cleary an issue with DNS resolution, as I never drop my Wifi and nothing will resolve. I work in IT for a living, so I am proficient on the troubleshooting side...just had FIOS so long, I forgot what a PITA COAX can be...

 

Thank you,

Rick

BruceW

Gold Problem Solver

 • 

22.8K Messages

8 m ago


@RCSII wrote: ... It is cleary an issue with DNS resolution, as I never drop my Wifi and nothing will resolve. ...

"Never drop Wifi" just means that you have a connection between your Wifi gateway or router and your computer or mobile phone/tablet or other device. If the link between the Wifi source and Comcast's network is broken you will indeed have "an issue with DNS resolution" because the equipment will not be able to reach the DNS servers -- or anything else beyond your home.

 

If you post the information requested we might be able to tell you if a connection problem exists.

 

Frequent Visitor

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6 Messages

8 m ago

Bruce,

 

Here you go. 

Model:TG1682G
Vendor:ARRIS Group, Inc.
Hardware Revision:12.0
SNR

40.37 dB

40.95 dB

40.95 dB

40.95 dB

40.95 dB

40.37 dB

40.37 dB

40.37 dB

40.37 dB

40.95 dB

40.95 dB

40.37 dB

40.37 dB

40.37 dB

40.37 dB

40.95 dB

40.95 dB

40.37 dB

40.95 dB

40.37 dB

40.95 dB

40.95 dB

40.37 dB

40.37 dB

Power Level

1.70 dBmV

1.80 dBmV

1.30 dBmV

1.40 dBmV

1.10 dBmV

0.80 dBmV

0.60 dBmV

0.80 dBmV

1.00 dBmV

1.00 dBmV

1.00 dBmV

0.70 dBmV

1.40 dBmV

1.20 dBmV

1.20 dBmV

1.20 dBmV

1.30 dBmV

1.00 dBmV

1.30 dBmV

0.60 dBmV

0.60 dBmV

0.00 dBmV

-0.20 dBmV

0.40 dBmV

 
Power Level

41.50 dBmV

39.50 dBmV

40.25 dBmV

41.75 dBmV

 

Nothing in the event logs except DHCP lease renewal. It has happened several times today, each on with erros on my systems about DNS resolution. Again, my VPN connected work lap top never drops the VPN, so the connection is good, but DNS stinks. 

 

Rick

BruceW

Gold Problem Solver

 • 

22.8K Messages

8 m ago


@RCSII wrote: ... Here you go. ...

The signals posted were good at the time they were collected. If the VPN connection is using your in-home Comcast Internet and truly does not drop when other devices report a DNS error, I'm at a loss what the problem might be. Maybe others will have insight that I lack.

 

Frequent Visitor

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6 Messages

8 m ago

I apreciate the effort Bruce.  Having been in IT for 20 plus years, it is really irking me. 

Visitor

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2 Messages

2 m ago

I experience this 5-6 times a day. I have screenshots. The issue I receive is no response from the DNS server. There a couple of reasons this could happen, DNS server is overloaded and could not respond, The load balancers have a configuration issue, there is an issue with the load balancers, The timeout setting on the DNS server does not have the proper setting to account for latency from server back to end user Xfinity Device. This also could be from the end user Xfinity router timeout. It would be nice if I could add another DNS server but Xfinity doesn't allow you to add another in their router. 

EG

Expert

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89K Messages

@user_e326dc

Please create a new topic of your own here on this board detailing your issue. Thanks. 6-month-old dead thread now being closed.
 

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