I switched some of my servers from "Public" to "Private" and suddenly we started having issues. This doesn't make any sense since we don't even have Windows Firewall enabled. We have a load balanced-firewall environment and it seemed that the DMZ-based web servers couldn't communicate with the PROD-based SQL servers.

MikeP276, A couple of questions as we begin on this: -Is the Windows Firewall turned off or Disabled? - This may not seem like much, but having the service running though the filters are offstill means that the service is invoked, and so plugging into winsock (this is how it filters traffic), it is just that the filters it would otherwise apply are turned off. I have seen instances where turning it off is not enough, ensure that the service is not running and is set to disabled. During my time in the Microsoft Networking queues the take we took was that the windows firewall is not really meant to protect servers as much as it is clients. -What version of the OS are you running on these servers, 2008? -What prompted the change of network setting? -Are the web servers in the DMZ those you made the change on? Are they multi-NIC machines? Do they have an external and an internal-DMZ interface? Any network teaming enabled? Some milestones for troubleshooting this would be -Find if the problem was the Web server talking to the SQL boxes or the SQL boxes responding to requests. I would start with a telnet command (if 2008 you will have to enable this through Server manager. See: http://cbfive.com/blog/post/Using-and-Installing-the-Telnet-Client.aspx). On the web server enter at the command-line: "Telnet <IP of SQL server> 1433" w/o quotes. This will check to see if there is at the very least a network connection between the web server and the SQL boxes. If this returns you have a pretty good idea that it is nothing on the network itself, but maybe the applications themselves, or a content filter in between. -Find out what else happened to the server during the time of the functional change. I cannot tell you how many times I would swear up and down that the box I checked was the cause of the problem, because right after that the issue occurred only to find out that an A/V update happened at the same time, or I downloaded a hotfix. I would really recommend that these other means be looked at. -Take a network trace. I have a feeling that taking a network trace of both ends here would tell volumes. If you need some help see: http://cbfive.com/blog/post/Taking-a-long-network-capture.aspx. If you are not savy with network trace and do not know anyone in your group that is I can try to help out. Obviously you do not want to post the capture to a newsgroup but you can use InitialAssist@cbfive.com to send it to me. Don't forget to give credit where credit is due, vote this as helpful if it helped you.

I will check all these things. They are Windows 2008, some Standard and some Web. This was quite the disaster and I made the NLA switches from Public to Private and all ____ broke loose. Thanks.