How do I remove a subdomain website that doesn't really exist?

[l008comm]

So I run my own server. My business website is the default web site of the server. Then I have many other web sites I also run off my server. Somehow, a sub-domain that doesn't even exist, has gotten into Google, and now when you search for my business keywords, you get this crazy subdomain on my ip website instead of my rel business website.

It serves the same website because non-existent domains that point to my server automatically match the default virtual host. So I can't make a robots.txt file because this stupid domain doesn't even exist. And it has knocked my real site off page one and taken its place as result #1. How can I fix this?

[edited by: tedster at 5:18 am (utc) on Mar. 14, 2008]
[edit reason] remove specifics [/edit]

[tedster]

If your server resolves a request for the subdomain, then that url actually DOES exist - your configuration of the server creates it. It seems to me you need to reconfigure the server so it doesn't resolve wildcard subdomains.

[l008comm]

Well I'd say its more of a DNS thing than a server config thing. However server config is the solution I went with. I made a 'default' virtual host that matches no domain names. Put a little note and thumbnails to all the sites hosted on the server. Threw up a robots.txt that blogs everything. Now if you type a non-existent subdomain, or my server's IP, you'll get this page instead of one of the other domains. I should get more IPs from my colocator. This is way off topic but is google thought to give your site a better ranking if your domain's ip points back to the same site as the domain?