Windows 7: DNS problems after connected to public network

janw · 02 Dec 2010

Hi!

I've got the following problem on my Lenovo ThinkPad SL510 running Windows 7 Enterprise x64:

When running my PC in my home network everything works fine. I can ping IPs on my network and i can ping their hostnames.

However, when I have been logged in into the wifi network at my school (WPA2-Enterprise) and return home (and logon to my home network), I am not able to ping or connect directly (via Windows Explorer) to the hostnames anymore. Using the IP instead works fine. I can only get rid of this problem if I do a system restore (Start Menu -> Accesories -> System Tools -> System Restore) using a restore point created before I logged into the school network. This problem is reproducable!

I have tried allready:
- ipconfig /renew
- flushing dns cache
- deleting the school network
- disabling IPv6 on all network adapters
- changing the network node type to "Hybrid" via registry - seems the school network changes this setting

I seriously doubt that this problem has something to do with either my router or the other hosts in my network.

This is the ipconfig /all output at the time the problem occurs:

Code:

Windows IP Configuration

   Host Name . . . . . . . . . . . . : sl510
   Primary Dns Suffix  . . . . . . . : 
   Node Type . . . . . . . . . . . . : Peer-Peer
   IP Routing Enabled. . . . . . . . : No
   WINS Proxy Enabled. . . . . . . . : No

Wireless LAN adapter Wireless Network Connection:

   Connection-specific DNS Suffix  . : 
   Description . . . . . . . . . . . : Intel(R) WiFi Link 1000 BGN
   Physical Address. . . . . . . . . : 00-26-C7-60-D6-3E
   DHCP Enabled. . . . . . . . . . . : Yes
   Autoconfiguration Enabled . . . . : Yes
   Link-local IPv6 Address . . . . . : fe80::1c43:a971:5e7f:113a%13(Preferred) 
   IPv4 Address. . . . . . . . . . . : 192.168.0.12(Preferred) 
   Subnet Mask . . . . . . . . . . . : 255.255.255.192
   Lease Obtained. . . . . . . . . . : Donnerstag, 2. Dezember 2010 17:08:14
   Lease Expires . . . . . . . . . . : Freitag, 3. Dezember 2010 17:08:15
   Default Gateway . . . . . . . . . : 192.168.0.1
   DHCP Server . . . . . . . . . . . : 192.168.0.1
   DHCPv6 IAID . . . . . . . . . . . : 318777031
   DHCPv6 Client DUID. . . . . . . . : 00-01-00-01-14-81-D8-85-60-EB-69-38-AD-35
   DNS Servers . . . . . . . . . . . : 213.191.74.11
                                       213.191.92.82
   NetBIOS over Tcpip. . . . . . . . : Enabled

Ethernet adapter Local Area Connection:

   Media State . . . . . . . . . . . : Media disconnected
   Connection-specific DNS Suffix  . : 
   Description . . . . . . . . . . . : Realtek PCIe GBE Family Controller
   Physical Address. . . . . . . . . : 60-EB-69-38-AD-35
   DHCP Enabled. . . . . . . . . . . : Yes
   Autoconfiguration Enabled . . . . : Yes

Tunnel adapter isatap.{E7B82ABE-DC9D-4C11-A0BD-7ECAB27EA4DD}:

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

Tunnel adapter Local Area Connection* 11:

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

Tunnel adapter isatap.{18DAD967-A1E6-4538-81BB-AEBE6522FCBD}:

   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 isatap.{78BEBDF9-6BA3-469C-8CC8-D141518DE791}:

   Media State . . . . . . . . . . . : Media disconnected
   Connection-specific DNS Suffix  . : 
   Description . . . . . . . . . . . : Microsoft ISATAP Adapter #3
   Physical Address. . . . . . . . . : 00-00-00-00-00-00-00-E0
   DHCP Enabled. . . . . . . . . . . : No
   Autoconfiguration Enabled . . . . : Yes

Tunnel adapter isatap.{EC5DDBF7-5517-4CBB-9C48-7E54695A5D1A}:

   Media State . . . . . . . . . . . : Media disconnected
   Connection-specific DNS Suffix  . : 
   Description . . . . . . . . . . . : Microsoft ISATAP Adapter #4
   Physical Address. . . . . . . . . : 00-00-00-00-00-00-00-E0
   DHCP Enabled. . . . . . . . . . . : No
   Autoconfiguration Enabled . . . . : Yes

Please help me!!! Thank you all!

Regards,

Jan

brady · 02 Dec 2010

those dns servers are from public Ip's where your DHCP/DG are internals... are those set statically?

janw · 02 Dec 2010

Quote: Originally Posted by brady

those dns servers are from public Ip's where your DHCP/DG are internals... are those set statically?

My router (Linksys WRT45GL) sets those DNS servers. I wondered about them, too. Funny thing is, the other hosts in my network have exactly the same DNS servers and can find my notebook using both the IP and the hostname!

brady · 02 Dec 2010

very weird -- ok so IPv6... You might want to disable that from your adapter(s).

chev65 · 02 Dec 2010

One possible problem I see is that it looks like you have your DNS servers designated in your IPv4 properties rather than letting your router handle the task? It may help to remove those DNS entries and let the router handle DNS. You can designate your DNS servers in the routers set up page. Most routers will show the DNS as the default gateway which points back to the router for the DNS servers.

I also noticed that your subnet mask isn't normal. With your default gateway of 192.168.0.1 the subnet mask should be 255.255.255 not 255.255.255.192, the 192 part may be left over from your schools network settings and may be causing problems.

If you need to connect to two different subnets you need to define the two different networks by going into your advanced TCP/ip settings and add the different subnets and IP's to the list "picture below"

I also noticed that you have extra tunnel adaptors in your ipconfig /all, those will sometimes cause problems with your network and can be delated by going into device manager, select the "view" option then choose "show hidden devices" at which point you will see them all and they can be delated.

Do not disable IPv6!

janw · 02 Dec 2010

@chev65
It was me that set the subnet mask 225.225.225.192. This was not changed from being connected to the school network. I cannot change ist to .0 as my router prompts "Out of range, please adjust start IP address or user's numbers.". Also, I do not think thats the problem because its the same setting for my other hosts.

There are no DNS servers set in the IPv4 properties of my network adapters, everything is empty.

IPv6 is still enabled.

I tried to set the gateways IP as a static DNS server in the router, but that doesnt change a thing.

Here's a picture of the routers config.

chev65 · 02 Dec 2010

That subnet certainly isn't normal, i'm not sure what is up with that. The correct subnet should be automatic and you should not need to add the 192 at the end, this makes no sense to me.

I would reset the router in either event, you should not need to add anything to the default subnet. Also, the static IP settings aren't meant to have your default gateway IP, they only work if you are using the correct range of IP's. Although static or DHCP shouldn't make a difference here.

It may help to see the ipconfig /all from when you are connected to the schools network.

janw · 02 Dec 2010

Quote: Originally Posted by chev65

It may help to see the ipconfig /all from when you are connected to the schools network.

That wont be possible till next Tuesday.

I really dont wanna touch my router. Allthough it may not be configured very well, it does a good job for my other hosts including my NAS.

The problem is gone if I do a system restore. That tells me that I have to look for the fix on my notebook.

brady · 02 Dec 2010

antivirus, vpn software, FTP software, proxy sofware/settings?

Restore: resets settings and newly installed software... do you notice any missing software from the restores? Do you use the same restoration point for this issue?

janw · 02 Dec 2010

Quote: Originally Posted by brady

antivirus, vpn software, FTP software, proxy sofware/settings?

Restore: resets settings and newly installed software... do you notice any missing software from the restores? Do you use the same restoration point for this issue?

Well, I think I shouldve told you that. I have installed Wireshark. I have allready uninstalled it. It was not installed in the restoration point... But, that is another thing I cannot try till next TUE. But Im gonna. And I'll tell you if it works, when I do not install Wireshark when in school.

Sorry I have not told you that earlier...

Windows 7: DNS problems after connected to public network

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