Laptops on Windows Domain sometimes have problems accessing internet when off-site

Posted by FSUScoot on Server Fault See other posts from Server Fault or by FSUScoot
Published on 2011-02-15T13:59:22Z Indexed on 2011/02/15 15:27 UTC
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Hi all--

We've had this problem for a long time. When users travel, sometimes they can't get internet access from a wired or wireless connection. Here are a couple examples:

1) A user goes to a hotel and tries to access the wireless in their room. They can connect to the access point. They open a web browser and they can't get re-directed to the hotel's login page. Because they can't log in, there's no internet access.

2) A user goes to another laboratory/university and tries to access the wired network. They connect, link is fine, PC gets IP from DHCP but no internet access. There's no login page to be re-directed to. It should just "work".

What I've found is that it's a DNS issue. Because the computer is on a Windows Domain, it seems it MUST use our DNS servers. Even if you connect to an outside network and do an ipconfig /all, it looks like everything is ok. It'll even show their DNS servers listed in the config. The computer just won't use the other network's DNS server. I found a reg key that keeps our DNS servers listed and it seems that they take priority every time:

HKLM\SOFTWARE\Policies\Microsoft\Windows NT\DNSClient

All the values under that key are for our AD domain. NameServer and Searchlist never change. What I've found is if the user edits the NameServer string and puts the DNS server of the network they're on, everything works just fine. They get re-directed to the hotel's correct login page or their internet access starts working. It's only a problem if the network they're on blocks outside DNS or a hotel that uses an internal name in their front page redirection that only their DNS server knows about, i.e., not public. If the re-direct page starts with an IP, like 10.10.10.10, it'll work just fine.

Obviously this isn't a fix for everyone. Most of my users are pretty knowledgeable so it’s easy for me to walk them through or send them a .reg file that they can edit and run.

This problem isn't limited to Windows 7. It was like this with XP as well. It's not hardware related. The problem exists on both wired and wireless, Intel or Broadcom, laptops or desktops.

Anyone else have this problem? Is there a GPO I can change that I missed? Got a good work-around for this?

Thanks for any help!

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