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Windows 7 network configuration problem


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I have two laptops, and each uses the wireless connection for every day purposes. I use IP network for this. DHCP is used to assign these addresses.

Whenever I need to move large amounts of data, I connect a cable to the home router, which can use 1Gb/s speed. I use the network for this, and there is no internet access over this network. These addresses are assigned manually.

However, both networks share the same LAN, through the switch/router.

This setup up works very well.

Recently, possibly as the result of an update, a strange behaviour is seen. When the cable is NOT connected, the wireless connection sometimes suddenly changes its "obtain DNS automatically" to "use the following DNS server address", and fills in a random ip address from the network. As a result, most internet connections no longer can be found.

Anyone any idea what could be causing this?


Bart Zorn


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I just disconnect the cable and leave the settings at what they are.

In the properties for the wired connection I only set the IP address and the netmask, nothing else, so the bogus DNS server address does not come from there.


A few more details: I run a WIndows 2008 R2 server with a domain and a DNS and a DHCP server. This server has two network connections, one in the range, the other in the range. Both are permanently connected to a two different switches which are connected to form a single LAN.


Thanks for your reaction!



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Ok so where does the wireless connection obtain its IP address from?

If you have DNS configured, it should be in the DHCP cpl on the server. In Server Options, option 006 configures which DNS servers to send along when a client gets an IP from the server.

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The wireless connections get their address and other data from the server. I have disabled DHCP in the router. When a laptop reboots (or a ipconfig/renew) it gets all the data ok. Option 006 in the DHCP server has the correct list of DNS servers.


But the problem is that every now and then, the DNS setting of the clients get changed to fixed, wrong values and DHCP can't help that.


Like I said before, I suspect that a Windows update caused this, but I have not been able to identify an update which maybe guilty.



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