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Windows 10 laptop with an elephant's memory for internal-only DNS server

I have a remote user who reported chronic connectivity problems with her new Windows 10 laptop. I had her do the netsh winsock reset catalog and netsh int ip reset reset.log commands to resolve her problems, which worked, but the next day they came back. Her current procedure is to start the computer, have no Internet access, run the commands, reboot, and have Internet access until the next day.

Recently we bumped into each other at a training event and she was able to let me look at the computer in its non-working configuration. What I identified was that name resolution was failing and when I did an NSLOOKUP, much to my surprise our internal DNS server address was listed instead of the hotel's DNS server. Her connection is DHCP-only and gets the internal DNS server when she makes a VPN connection.

We were able to repeat the NSLOOKUP test once she returned home and saw the same thing: the inaccessible internal DNS server listed instead of her ISP's DNS server. We have a number of other employees with the same setup but none of them have reported this problem and I haven't been able to find much online about it.

Does anybody have a suggestion on what we can do to keep the computer from remembering this temporary DNS setting forever?
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Hello There

Go to Settings -> Network and Internet -> Status -> Network Reset -> confirm

Also while experiencing the issue, go to Settings -> Network and Internet -> Status -> Network Troubleshoot
Also check out HOSTS file.
run:
ipconfig /flushdns
ipconfig /registerdns

Checked DNS server if there is an A record for the hostname with the faulty address.
Set DNS scavenging.
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ASKER

I checked the HOSTS file at the hotel. It was clean. The laptop is not registering itself on the internal DNS server, which is not accessible anyway unless she VPN's in first. The laptop is starting up with the internal DNS persistent from (I guess) the last VPN connection.

I have asked the user to try Settings -> Network and Internet -> Status -> Network Reset -> confirm and see if that sticks, or if the problem returns the next day.
This morning my user tried the network reset and after rebooting the correct DNS server appeared in NSLOOKUP but her built-in Microsoft L2TP VPN connection started returning "A connection to the remote computer could not be established.  You might need to change the network settings for this connection." I uninstalled her WAN miniports and detected them in Device Manager to resolve that problem.

Tomorrow we find out if the network reset permanently resolved her problem or it returns on restart as it has in the past.
After network reset you will have to set VPN if the user uses it.
The user reported this morning that last night she left her computer on and with the VPN connection enabled, and when she returned to work this morning, the VPN connection was down but the internal DNS server used by the VPN connection was still being used as shown by NSLOOKUP, breaking name resolution needed for Internet access. She restarted the computer and it worked normally She re-established the VPN connection.

After a time the VPN connection dropped, and returned an "Element not found" error when she tried to re-establish it. NSLOOKUP showed the VPN connection's internal DNS server was still being used. After yet another restart the computer returned to normal.
I've observed a second user with a similar problem. He complained that his VPN connection drops sporadically and when it does he can't reconnect and has to restart the computer. We discovered that when the VPN connection drops, the DNS listed in NSLOOKUP was still the internal DNS server of the VPN connection; not his router/ISP's DNS server. I had him try ipconfig /flushdns but it didn't resolve the problem.
I was able to get this to happen in the office and observed that after the VPN was dropped the PPP adapter was still listed in IPCONFIG /ALL with a media state of "Media unoperational" and the same NSLOOKUP symptom. I found this: https://social.technet.microsoft.com/Forums/windows/en-US/efd7c70c-e652-4101-93ac-2c57884e162e/no-internet-access-after-disconnecting-from-vpn?forum=w7itpronetworking

and using ROUTE CHANGE 0.0.0.0 MASK 0.0.0.0 192.168.2.1 METRIC 1 IF 6* was able regain Internet access and NSLOOKUP displayed the correct DNS server.

*6 was the network adapter being used, as displayed at the top of ROUTE PRINT.
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Uninstalling the Dell SonicWall Global VPN Client was the only solution that permanently cleared the error state. The other solutions either did nothing or did not prevent the error state from returning.