Lan settings

In Control panel, Internet options under the connections tab. in the lan settings does the automatically detect settings need to be checked? Also is there a good program that checks your IP and the rest of of your settings to see if your configured right? I used a program on ipchicken.com and it showed my IP right right but got my browser and OS wrong. it said I was using Mozilla when I'm using IE. It also said I was using NT5.1 when I'm using XP.