Problems connecting to websites: cannot find DNS server

[sylviesinc]

Thanks for the advice. I'm leaving it as is for the moment. Silver Lounger said that the primary and secondary should be from the same server but the server namebench mentioned only showed one configuration so I'm unsure what to put as the secondary. I know that they are similar but different as they are now.

[Roderunner]

Just about any router will have to be reset after a DNS change such as you did, so it is most likely that yours reset itself, which would have dropped his wifi connection. However, it seems as though his PC did not re-connect after that as it should have done (or got "confused" in the process) - see if restarting it does the trick.

I did a clean install of my wired pc a few days ago and had to uninstall the Network adapter on my Laptop, reboot, then reconnect.

[arocee]

I did a clean install of my wired pc a few days ago and had to uninstall the Network adapter on my Laptop, reboot, then reconnect.

I am curious as to how updating one PC could affect another one's connection settings for a common access point/router unless they are in some sort of ad hoc or peer arrangement, or Internet Connection Sharing (ICS) with the wired PC providing the ICS service to the laptop, instead of each independently connecting directly to the router/access point. That latter configuration (direct connection) should avoid any such interdependence between PC's.

The other possibility that occurs to me in sylviesinc's case, is that the update of the router for the DNS server also (accidentally) disabled wifi access, or altered its configuration in some way such as zapping the encryption key. sylviesinc, have you checked the router status to see if the wifi setup is active and unchanged?

HTH

[sylviesinc]

All I know is that as soon as i changed my router's DNS server config back to the original, my husband's laptop connected as usual.

[Roderunner]

I am curious as to how updating one PC could affect another one's connection settings for a common access point/router

I'm afraid I'm not clever enough to know why, all I do know was my connection was very slow beforehand.

[xpuserpjc]

The recommendation and tasks changed the DNS settings on the router and all devices go to the ISP through the router. The changed DNS settings were there. Most devices (laptop, tablets) are set to DHCP, which dynamically assigns a local/LAN IP address and handles DNS queries. In comparison, I do testing on my computer using OpenDNS and the other devices show no impact.

[arocee]

The recommendation and tasks changed the DNS settings on the router and all devices go to the ISP through the router. The changed DNS settings were there. Most devices (laptop, tablets) are set to DHCP, which dynamically assigns a local/LAN IP address and handles DNS queries. In comparison, I do testing on my computer using OpenDNS and the other devices show no impact.

Exactly my experience - I have done a fair amount of DNS switching to find the best service, and for the PC's in my household, a mix of Linux and Windows, I have only had to point them to the routers (I use cable and DSL services for redundancy since I work from home most of the time) via DHCP, and they use whatever DNS service the routers have been configured for. I also have done testing with explicit settings on a particular PC to override the router setting.

I am thinking another way the laptop could have been messed up by the router DNS change would be if it has some security settings or related software that require a specific DNS service - have not seen anything like that before, but I see how it could be possible. Maybe it has a VPN setup that depends on a name-to-IP lookup that can only be resolved by the original DNS service from the ISP, and not by the alternative DNS service that was tried?

That would explain why the laptop PC could not get to anything on the Internet if it does all access exclusively through its VPN connection. My work VPN connection works that way, but, my VPN setup uses hard-coded IP addresses to initially connect to the corporate network, so no DNS lookups are done and it does not matter what DNS service the router uses. Also, this does not happen until I manually start up the VPN software, so I can access the Internet from my work PC via my routers' DNS lookups until I sign into the VPN. After that, "work rules", and that may be the case immediately upon startup of the problematic laptop - no option to use any other DNS service, and it can only find the VPN connection via the original DNS service, although that would seem to be a fragile arrangement if so easily broken by changing router DNS service. All blue-sky what-ifs here, I have to admit, but plausible.

sylviesinc, how about a simple test of my hypothesis? On both PC's run cmd.exe (assuming Windows OS on your PC's, and you are back to a working router setup) to get a command line window, and run the command nslookup with the name of some web site both of your PC's can access - e.g.:
nslookup www.google.com

This should get a reponse (based on my Windows 7 work PC - I think XP might show the results a bit differently, but basically the same info) with Address and Server for the DNS service, then a block for google (usually multiple IP's) as a "non-authoritative" answer. Does that "server" name match for both the wired and wifi PC's? The wired one at least should show either your router's internal IP that your home network uses, or possibly the DNS server IP that is configured for the router. Does the laptop PC show the same server? If not, then I am thinking it is using a VPN for all access (is the laptop a work-provided PC?).

If the laptop settings are "hardwired" for the ISP DNS service somehow, then maybe we can look at doing something equivalent for the desktop and set its own DNS configuration to override the router's, and use the faster DNS service directly.

FWIW

P. S. sylviesinc, this has got my curiosity going, and I think if we find out how the laptop's networking is configured, we may be able to resolve this so you can get faster DNS lookups without "breaking" the laptop connection, but feel free to ignore if too much hassle ;-}

[sylviesinc]

I tried this as you suggested (cmd.exe on both) and they both show the same IP address first. The PC also shows multiples of a different address. No neither are work computers. (The laptop is XP and the PC Vista.)

[bethel95]

Your probably using your ISP's DNS servers. Download this to find your best option.

In addition to the above-linked tool (namebench), Gibson Research offers DNSBench. I've used it, and found it quite helpful. Of particular interest is a feature that builds a custom DNS server list for your specific physical connection. Note that building the custom list isn't the same thing as running the benchmark.

FYI, I also use and recommend OpenDNS, primarily for the content filtering feature. When I ran the custom DNS server list on DNSBench, I was happy to see that the top two servers were the two OpenDNS servers that I was already using.

For those of you who aren't familiar with Gibson Research, it's run by Steve Gibson, former InfoWorld columnist and current co-host of the Security Now podcast (at twit.tv).

[arocee]

I tried this as you suggested (cmd.exe on both) and they both show the same IP address first. The PC also shows multiples of a different address. No neither are work computers. (The laptop is XP and the PC Vista.)

Is that first, common address your router or the DNS server IP?

[sylviesinc]

It's my normal IP address since I went back to using my ISP's server. (It's the address that always shows when I'm conducting a speed test.)

[BigMac56]

Another test to see what's going on would be to run "ipconfig /all" from a cmd box. Then compare DNS Services between machines.

[Oksana]

When using the recommended "namebench" software, Malwarebytes blocked about ten different websites.

[sylviesinc]

It's all too much hassle, but thanks for all your input. I may try again another time, if get really fed up with the DNS server errors.