I am having an issue with the wild card domains. We use Windows 2003 Server.
We have created a wild card entry in the DNS settings for one of our websites. We did this as we needed to create around 20 sub domains.
We have configured the sub domains in the IIS like sub1.mydomain.com, sub2.mydomain.com etc, each of them directed to respective folders.
Lately we have observed an issue. Google has reported that we have relatively huge amount of pages (around half a million). But in real, we don't have that many pages.
We we did our home work we have identified that entering a non-existing (or non-defined) sub domains like asdfsf.mydomain.com is loading the contents of www.mydomain.com.
Our Thinking: There may be a wrong link in a sub domain, which is connecting to a folder which is available in the main domain.
In Detail: Let's imagine we have this folder, www.mydomain.com/message-board/. Due to the wrong link, user will be able to access the same page like this sub1.mydomain.com/message-board. Search engines treat this as a different page and index it and therefore the total number of pages get increased.
Now the question is, what should I do in IIS to load an error page when a user enters a non-existing sub domain? And also, is our thinking correct? Please Help!