Question : Exchange server on 2 different domains

I have a test domain set up on a virtual machine which is not part of the main enterprise forest.  I want to install Exchange on this box for testing purposes.  As I was in the process of installing Exchange, it requires access to the internet for updates and whatever else.  The only way I can think of to give it internet access was to add a new virtual nic and give it an IP from my current domain that is a member of the enterprise forest, and have it go through our main proxy.  However, I am concerned that if I do this the other domains in the forest may see that there is another Exchange server in existance and start routing mail through it.  I eventually want to install Live Communications server as well for testing and would have the same kind of concerns.  Is this possible?  Am I going about this the wrong way?  Is there a better way to do this?

Answer : Exchange server on 2 different domains

Domains don't automatically detect Exchange installations and if it is in a test domain, it's basically segregated from all other domains on your network. Mail routing has to be set up manually, and there is nothing dynamic about it for the most part. You should be just fine connecting it to the internet as long as you don't supply it with the IP address of the Exchange server that is routing Internet mail. You should also be able to set up Live Communications server on your test domain without issues as well.