DSN Server problem

this is the message i'll receive

This site can’t be reached

search.yahoo.com’s DNS address could not be found. Diagnosing the problem.

In theory, using the DNS servers directly upstream from you should be faster, but I have found that is simply not the case with Xfinity in two different states.  In fact, I found them to be pretty unreliable in general with frequent timeouts like you describe, and also very slow to propagate SOA changes.

On the new gateways, I guess they removed the ability to set alternate DNS for some reason.

What you can try, is setting static DNS servers on your client instead of using the DNS servers passed out by your gateway.  Try google or cloudflare (8.8.8.8, 8,8,4,4)  or (1.1.1.1, 1.0.0.1).  See if it works any better.

@grady777 

FWIW, many times, with many browsers, a general connection problem/impairment manifests itself as a generic DNS error/problem when it actually isn't. 

Go here and see if anything applies;

https://forums.xfinity.com/t5/Your-Home-Network/Internet-Troubleshooting-Tips/m-p/3310447#M316652

I was doing some research, i noticed all my browsers were configured to use a proxy by default, each browser i looked at had the same proxy setting. Enable Dns over https and use provider Cloudfare as the default, did anyone else notice that, i am curious since comcast uses its own Dns servers, if there could be some kind of conflict at times

Its a firefox default now (probably many others too) to try to use DoH.  I think it may be off by default on Chrome still, but that may change.  It avoids a plain text DNS query.  More on that here:

https://support.mozilla.org/en-US/kb/firefox-dns-over-https

Generally, a good thing, but combined with other network issues that's possibly an issue too.

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@flatlander3 wrote:

 

On the new gateways, I guess they removed the ability to set alternate DNS for some reason.

 

What you can try, is setting static DNS servers on your client instead of using the DNS servers passed out by your gateway.  Try google or cloudflare (8.8.8.8, 8,8,4,4)  or (1.1.1.1, 1.0.0.1).  See if it works any better.

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As I've stated before, you can't even change the DNS servers in the individual network clients anymore as the Comcast supplied gateway devices also no longer act as DNS relays / DNS forwarders.

Well, there you go.  Yet another reason on top of the $14 monthly rental charge to use a 3rd party gateway. 🙂

@jlavaseur 

Speeds / throughput have nothing directly to do with DNS. Don't care what the proxy is. If the gateway doesn't forward the DNS queries to what ever server, it won't work. The Comcast in house DNS servers are hardcoded into the the firmware of the Comcast gateways. The newer firmwares also don't allow the gateways to act as DNS proxies / forwarders any longer as I stated. They used to allow DNS forwarding in the past but they have now disabled that feature. They say it is for security purposes.

Something else is going on.

@EGthis what confuses me, Firefox install defaults to using a proxy, Cloudfare, with it on i get super speeds

with the proxy set to off, i still get great speeds but not quiet as fast, so there seems to be another Dns server involved, there is a speed difference with it on or off