I have developed an `ASP.NET` website and deployed into my IIS server. Now to see that my IIS is installed fine, I type local host in my address bar, and I get the welcome screen of IIS and its documentation in a separate window. 

Now I gave the url of my website `http://localhost/mysites/site2/Default.aspx` I access my site. Also giving my IP address instead of local host like: `http://192.168.1.46/mysites/site2/Default.aspx` also works. 

Just out of curiosity I wanted to see what happens when I give my IP address in addressbar. It asks me a user name and password saying:`The server 192.168.1.46:80 requires a user name and password`. 

I donot know what user name and password it is asking, and as of my knowledge I thought localhost points to my own IP address internally. But what is the difference and also what username and password do I need for it? 

**Update:** On chrome and IE just giving localhost displays the welcome screen, but on mozilla, localhost is also asking for a username and password.