# Cannot Connect to DNS Server



## lilshu (Jun 15, 2009)

Hi guys! I've been trying to get help for this on another website, but they're not doing much... I thought I might post this in a website who has more than 3 tech savvy users! Especially since I need this working in the next three days, or I'll have to put in some time at the library.

So around two weeks ago, I moved into a set of apartments that share three different wireless networks, that were recently installed by Comcast. For the first week, everything worked perfectly- I was able to connect to them, and use the internet. Then, about a week later, I found a Trojan (Trojan.BHO) through Malwarebytes Antimalware- I cleaned that up, and thought that'd be the last of that.

But after doing that, whenever I'd connect to one of those wireless networks, I would be allowed local access, but not internet access. (I don't know if that has anything to do with the Trojan removal.) When I would try and open Firefox while connected to the network, it'd take maybe 3 minutes to actually open, and then it would never load a page. When I tried viewing a webpage on IE, it gave me an error that the DNS Server could not be reached. I ran the diagnostics tool, and it returned an error: "Cannot communicate with primary DNS server. Network Diagnostics pinged the server, but did not receive a response."

And that's the point I'm at now. The person who was helping me earlier was deadset on my problems being caused by a trojan, which may be true. While Googling around, I found a lot of issues with a "6to4 Adapter," which seems to fit what's going on here. (But when I went into Device Manager to disable the 6to4 Adapter, there wasn't one listed.)

My computer is an Inspiron E1505 running Vista 32bit SP1. It's using the standard 1390 WLAN Mini-card. I've scanned through recently, and found no trojans or viruses.

Thanks for any help you guys can offer! I'll try and check with this thread as often as I can.


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## lorjack (Nov 15, 2007)

*Windows Vista*
Open up a command prompt (Start > All Programs >Accessories > alternate click on Command Prompt > select "Run as Administrator"
Type the bolded commands into the command prompt window:

Reset WINSOCK entries: *netsh winsock reset catalog*
Reset IPv4 TCP/IP: *netsh int ipv4 reset reset.log*
Reset IPv6 TCP/IP stack: *netsh int ipv6 reset reset.log*

When finished reboot


Supply the following information please.

OS running on all affected systems
*Make & models* of all equipment (routers, network cards, modems).
Wired or wireless? 
What wireless encryption is in use? (WPA, WPA2, WEP, None)
Browsers being used (Firefox, IE, Safari, Opera,...)
What security software is installed? (Firewalls, AV, Spyware, Malware,...)

Open up a command prompt (Start > run > cmd)
Type the following bolded commands and post the results for each affected machine.

*ipconfig /all*
*ping www.google.com *
*ping 74.125.53.99*

Note: To post results of commands, alternate click on the top of the command prompt > edit > select all >
alternate click on the top of the command prompt > edit > copy > paste in a message here. If you are on
a computer that can't connect to the internet then paste the contents in a text document and save it to a
portable media like a flash drive, then use an internet capable machine to post the contents.


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## lilshu (Jun 15, 2009)

Okay, I followed those command prompt steps- but first the information you requested.

*OS*: I don't know if anyone else is having this problem. I never see any neighbors that use the wireless connection- I'm not even sure there are others using the connection. But I'm running Windows Vista Home Premium SP1.

*Hardware*: I'm not sure about anything other than my computer- everything else was installed by Comcast for the building, and is locked in a communications closet somewhere nearby. No one has a key. I'm guessing it's a typical Comcast Cable modem with a Linksys router, from one of the network names. My computer is an Dell Inspiron E1505, that uses the standard Dell Wireless 1390 WLAN Mini-Card.

*Encryption*: It's an open public wireless network- so no encryption.

*Browsers*: I've used Firefox and Internet Explorer (Both latest versions), and neither one works.

*Security Software*: Windows Firewall (turned off), Windows Defender (On), MWB Anti-malware, and Hijack this are the only software I have installed for security. 

*IPconfig:*

```
C:\Users\William>ipconfig /all

Windows IP Configuration

   Host Name . . . . . . . . . . . . : WilliamsPC
   Primary Dns Suffix  . . . . . . . :
   Node Type . . . . . . . . . . . . : Hybrid
   IP Routing Enabled. . . . . . . . : No
   WINS Proxy Enabled. . . . . . . . : No

Wireless LAN adapter Wireless Network Connection:

   Connection-specific DNS Suffix  . :
   Description . . . . . . . . . . . : Dell Wireless 1390 WLAN Mini-Card
   Physical Address. . . . . . . . . : 00-18-F3-A7-14-0E
   DHCP Enabled. . . . . . . . . . . : Yes
   Autoconfiguration Enabled . . . . : Yes
   Link-local IPv6 Address . . . . . : fe80::bc14:4371:c68a:5367%13(Preferred)
   IPv4 Address. . . . . . . . . . . : 192.168.1.124(Preferred)
   Subnet Mask . . . . . . . . . . . : 255.255.255.0
   Lease Obtained. . . . . . . . . . : Monday, June 15, 2009 11:02:22 PM
   Lease Expires . . . . . . . . . . : Tuesday, June 16, 2009 11:02:22 PM
   Default Gateway . . . . . . . . . : 192.168.1.1
   DHCP Server . . . . . . . . . . . : 192.168.1.1
   DNS Servers . . . . . . . . . . . : 192.168.1.1
   NetBIOS over Tcpip. . . . . . . . : Enabled

Ethernet adapter Local Area Connection:

   Media State . . . . . . . . . . . : Media disconnected
   Connection-specific DNS Suffix  . :
   Description . . . . . . . . . . . : Broadcom 440x 10/100 Integrated Controlle
r
   Physical Address. . . . . . . . . : 00-15-C5-C6-5D-12
   DHCP Enabled. . . . . . . . . . . : Yes
   Autoconfiguration Enabled . . . . : Yes

Tunnel adapter Local Area Connection* 6:

   Media State . . . . . . . . . . . : Media disconnected
   Connection-specific DNS Suffix  . :
   Description . . . . . . . . . . . : isatap.{0FB95878-7F9C-47F8-ACB2-4A556994B
1DA}
   Physical Address. . . . . . . . . : 00-00-00-00-00-00-00-E0
   DHCP Enabled. . . . . . . . . . . : No
   Autoconfiguration Enabled . . . . : Yes

Tunnel adapter Local Area Connection* 7:

   Media State . . . . . . . . . . . : Media disconnected
   Connection-specific DNS Suffix  . :
   Description . . . . . . . . . . . : Microsoft ISATAP Adapter #2
   Physical Address. . . . . . . . . : 00-00-00-00-00-00-00-E0
   DHCP Enabled. . . . . . . . . . . : No
   Autoconfiguration Enabled . . . . : Yes

Tunnel adapter Local Area Connection* 9:

   Media State . . . . . . . . . . . : Media disconnected
   Connection-specific DNS Suffix  . :
   Description . . . . . . . . . . . : Teredo Tunneling Pseudo-Interface
   Physical Address. . . . . . . . . : 02-00-54-55-4E-01
   DHCP Enabled. . . . . . . . . . . : No
   Autoconfiguration Enabled . . . . : Yes
```
*Ping Results:*

```
Microsoft Windows [Version 6.0.6001]
Copyright (c) 2006 Microsoft Corporation.  All rights reserved.

C:\Users\William>ping www.google.com
Ping request could not find host www.google.com. Please check the name and try a
gain.

C:\Users\William>ping http://www.google.com
Ping request could not find host http://www.google.com. Please check the name an
d try again.

C:\Users\William>ping 74.125.53.99

Pinging 74.125.53.99 with 32 bytes of data:
Reply from 192.168.1.1: Destination net unreachable.
Reply from 192.168.1.1: Destination net unreachable.
Reply from 192.168.1.1: Destination net unreachable.
Reply from 192.168.1.1: Destination net unreachable.

Ping statistics for 74.125.53.99:
    Packets: Sent = 4, Received = 4, Lost = 0 (0% loss),
```
If it helps any, there are wireless networks that I am able to connect to, it's just this building's set of wireless networks that I cannot connect to.


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## lorjack (Nov 15, 2007)

Disable all security software. I'm sorry to say but this looks like a malware problem. Even if you removed the Trojan you found there usually is other pieces still left on the system.

Are you able to get internet connectivity on other networks?


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## lilshu (Jun 15, 2009)

I disabled all the security software that might be blocking something, and it still didn't work.

I am able to connect to other networks- out of the 6 or 7 in the area, the three that were installed by Comcast are the only ones giving me problems. Last night I was messing around in Device Manager, and disabled IPv6, which gave me access to one of the networks that was problematic before, but there are still 2 (the primary two that I should be using) that won't connect to the internet.

How sure are you it's malware? 3 individual up-to-date scanners haven't been able to find anything thus far.


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## appatight (Sep 19, 2007)

It would be really helpful if you knew if someone that could hook up to that wireless network for you and try to ping outside the network like to google or yahoo. If you can then post what happens when another computer try.


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## lorjack (Nov 15, 2007)

Refer to this thread and try what Johnwill posted.
http://www.techsupportforum.com/f137/solved-vista-not-compatible-with-router-246559.html


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## lilshu (Jun 15, 2009)

appatight said:


> It would be really helpful if you knew if someone that could hook up to that wireless network for you and try to ping outside the network like to google or yahoo. If you can then post what happens when another computer try.


I wish that were possible.



lorjack said:


> Refer to this thread and try what Johnwill posted.
> http://www.techsupportforum.com/f137/solved-vista-not-compatible-with-router-246559.html


So I changed all the settings he recommended, tried connecting, but it still had the same issue. I then checked to make sure all the settings had been changed, and they had, and then I rebooted. I checked the settings again, and they were all what they should be, but the problem still exists.

That's more the kind of advice I was expecting. I'm surprised it didn't work...


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## lorjack (Nov 15, 2007)

OK, do the registry fix located here. Do not forget to make a backup of the registry first.
http://www.techsupportforum.com/mic...ur-wireless-network-tried-everything-try.html


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## lilshu (Jun 15, 2009)

I wish I could say that worked. I'm starting to think I shouldn't just drive home this weekend and snag a copy of XP to install. Vista has been causing almost as much trouble as Ubuntu!


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## lorjack (Nov 15, 2007)

Follow this guide on fixing system files, they may have been damaged when the Trojans were removed. You will most likely need your Vista disc.
http://www.updatexp.com/scannow-sfc.html


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