Our company is in the process of transitioning from an old to a new proxy server. Clients IE browsers are configured by the automatically detect settings feature via DHCP option 252. As we wish to trial the new proxy server first we have created an alternative WPAD file for this purpose.
Option 252 in DHCP was usually configured in this way - http://
<server name>.<domain name>:80/wpad.dat. This has worked well for a number of years. We want to trial the new proxy at a number of sites so have configured DHCP option 252 for those sites as follows- http://
<server name>.<domain name>:80/wpadnew.dat. We had found that this was working and clients at the trial sites were picking up the wpadnew.dat file without issue. In the last week or so some strange things have been happening.
1. With Option 252 for a particular scope set to the new WPAD file, clients still retrieve the http://
<server name>.<domain name>:80/wpad.dat file.
2. At a site with more than one scope (with all scopes configured with option 252 for the new file) clients on some scopes retrieve the new file while clients on the others still retrieve the old file.
3. If I move a client from a scope where it should have retrieved the new file, but was still retrieving the old to a subnet where the clients were able to retrieve the new file, it will successfully retrieve the new file and when I move it back it still retrieves the new file.
To me it seems like perhaps some scopes aren't providing DHCP option 252 information to the clients so the clients are just working from the cached file and settings in the registry. Has anyone seen anything like this before?
Domain controllers are Windows Server 2008 R2 and clients are Windows 7. IE version is 9.