Windows 7 x64 and Wireless DNS issues
I have a user with Win 7 Enterprise x64 on his D830 laptop. Suddenly, his wireless stopped working. It will connect to the network fine, and DHCP provides IP, DNS, etc. He cannot browse anywhere though. If you connect via IP address it works, but no DNS resolution is occurring. This happens on our company networks and his personal network at home. Wired connection works just fine. Only the wireless has this issue. We have updated all drivers, swapped the mini-PCI wireless card for a known good one, disabled IPv6, deleted all profiles and recreated...nothing. Ping by IP...works...ping by DNS name...cannot resolve. Tried Firefox and IE for browsing, same issue. Nothing in the network adapter properties shows any different to a fully functional D830 with Win7 x64 next to it. Any ideas? Thanks Ross
March 5th, 2010 8:18pm

I'll have to look again in the Event Viewer when he gets into the office today, but the DNS client works for the wired connection just fine. You can connect to the wireless system and be unable to browse, plug an ethernet cable in and off you go. I might be mistaken, but I don't believe each connection has its own instance of the DNS client. Ross
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March 8th, 2010 6:03pm

All wireless adapter settings match a fully functional device. DNS server addresses are provided by DHCP as normal, and you can ping them. Firewall is off by default. Anti-virus being disabled made no difference. We have the latest drivers for the Dell 1390 wireless card installed also. The machine exhibits no other behaviors of malware, and scans clean with Malwarebytes Anit-Malware and Sophos AV. This is why we thought it might be hardware failure at first. We checked the antenna connections and they were tight, so we swapped the 1390 card from another D830 that we know was working. Same issue persisted. If DNS was totally hosed, it wouldn't work for the wired connection. It's odd that it only affects the wireless, and only DNS. Again, you can load a webpage by IP address, you just cannot resolve any of the links on that page. Disconnect from the wireless and plug in ethernet, and off you go. Ross
March 9th, 2010 4:46pm

We disconnect from the wired connection. Not a router issue as this is a corporate network...Cisco ASA 5520 firewalls and Aruba 3000 wireless system. Wired connection is to a Cisco 3560 linked to a Cisco 4948 before the firewalls. It works fine for almost 300 other users in the office, so it is machine specific. The firewall on the laptop is disabled by group policies on the domain also. We have three different wireless networks on the Aruba system each using different VLANs for different layers of access and this unit will not work on any of the three. Also, the security method is different on each wireless network. One uses PEAP and RSA token, one uses WPA2 Enterprise linked to their domain SSO, and the last uses a PSK generated by the Aruba system for time-based guest access. Not sure what his setup at home is, but it does the same. Wired works, wireless doesn't. I've pretty much tried all the suggestions prior and no luck. Just trying to avoid rekicking the system and migrating a lot of data, plus installation of apps that are not part of the standard image. Thanks Ross
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March 10th, 2010 4:33pm

The user has been traveling and is supposed to be back int he office this week. I'll get a disc to scan with from one of the lead techs on our Linux teams. I've seen DNS hijacking here before and it never left one interface alone while the other stayed functional. And it exhibits no other behaviors of malware either. It is not doing anything very sneaky on the network because the IDS hasn't reported it...and this thing reports some legit stuff as suspicious if it crosses a certain threshold. I'll scan the disk as soon as an opportunity presents itself and report the findings back. Ross
March 15th, 2010 5:14pm

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