They don't look at your machine specifically. They look at all domains on the entire internet and simply do a host lookup on the domain to resolve the domain name to the ip address. In your case, all those domain lookups point to your server box and IP(s).

There is nothing you can do short of removing the domains and changing the dns to stop it. This is just the way the net must work.

Thanks for the reply.

I understand that if I conduct a WHOIS search for 'mydomain.com' that dns/nameservers resolve this domain to an i.p. number, and hence the host machine is located via this i.p. number.

But once having found my machine, do they query apache or some other service on the host machine to list all the other domains on this machine (myotherdomain1.com, myotherdomain2.com etc.) or do they search the millions of dns records to find domains with a matching i.p. number?

How do they actually find all the other domains hosted on my machine - a query to the host machine or an exhaustive dns search of all domains that have matching i.p. numbers?

numnut - here's an example. Assume that the internet is made up of 5 domains and that IP addresses are only 3 numbers long.

Domain - IP
domain1.com - 111
domain2.com - 111
domain3.com - 111
domain4.com - 123
domain5.com - 124

Now, it's easy to imagine that if you have a list of all 5 of those domains you would simply run whois against all of them and get back the list of IPs. Based upon the IP address it would be trivial to be able to say:

"domain1.com, domain2.com and domain3.com are all on the same IP address (and probably the same server). domain4.com and domain5.com appear to be on their own servers".

Now, imagine that you have a really large server. You just use the same process on all of the domains on the whole internets. Then you know the status of the servers. It has nothing to do with an apache setting or anything else. You could make domain1.com look like it were on its own server by getting it a static IP, but that doesn't fool everyone (netcraft, for example, tries to guess a server beyond just the IP addresses).

Welcome to WebmasterWorld, NumNut.

If you truly want only your domain listed you'll need to get your own IP address, as greggles mentioned.

And welcome to WebmasterWorld too, greggles.

This is but one of the reasons why running multiple websites on the same IP address is unprofessional and unadvised.

I know that excludes some of the really cheap hosts.

For the most part, a host will charge no more than $1/month for an IP address. My host charges a one-time $2 setup fee, and $0/month.

You just have to make this a criteria when deciding on a host. It doesn't have to be an undue expense.