I have a Windows 7 laptop which I regularly use to access wireless internet when traveling. Normally, everything connects and functions as expected, but as of 4 days ago, I have noticed that I am unable to open websites after connecting to the access point.
I finally got around to doing some investigation tonight and discovered that the problem lies with the DNS name resolution. Right now the IPv4 configuration is configured to use a DHCP assigned IP and DNS. Per ipconfig /all, I can say these dynamic values (IP, Gateway, DNS, ec.) are being assigned correctly -- but I am unable to surf the web. However, if I manually specify a DNS server (e.g. Google's 126.96.36.199) name resolution occurs as expected and everything works.
I never had to manually specify values in the past and I don't want to start now.
If you're like me, you probably suspected my DNS server as the culprit. Unfortunately, I have several other devices that do work correctly with my DNS server: Windows XP, Apple iPad, iPhone, and Windows Surface device. Each of these devices work correctly with DHCP (no manual configuration).
The problematic laptop has always worked correctly prior to 4 days ago.
To troubleshoot, I removed my manual DNS setting for Google and ran Wireshark. This revealed an interesting discovery: instead of seeing DNS requests as I attempted to load websites, I only see requests for NBNS -- which will fail because I don't have an NBNS server.
I also ran a netsh->dnsclient=>show state on the troubled laptop:
Query Failure Behavior : Always fall back to LLMNR and NetBIOS if the name does not exist in DNS or if the DNS servers are unreachable when on a private network
Query Resolution Behavior : Resolve only IPv6 addresses for names
These results make me think that we're hitting a fallback state, but as I said, I don't see the system attempting to use DNS at all.
I'm also perplexed why the system would resolve only IPv6 addresses -- I am only using IPv4 (IPv6 is not selected on the adapter configuration)
Anyways, I'm perplexed. It works if I manually specify the DNS server, but DHCP configuration fails (despite ipconfig /all showing the correct values were assigned via DHCP)
Any suggestions/ideas are welcome.