So I started installing Exchange today. I did the schema updates and prepare alldomain command. I have now attempted to run the setup and ran into a problem. My domain has a _ in the domain. From what I have read, it seems like the only options are to change my domain name, or add a new domain tree?? Companya_local is where I ran all the updates and started the install. Companyb, does not have the underscore in it's domain name. I was thinking of installing Exchange in that domain, however, Companyb is a sister company of Companya_local and I'm not sure about how NDR's are configured. Would NDR messages that are for Companya_local appear as if they are from Companyb? If so, is there a way around this? My other issue is that if Companyb was sold, then I would still have an Exchange server in that domain. So maybe it would make since to create another domain tree.
When creating a new domain tree, does this mean I have to import all users to this domain? How would I configure my mail from Companya_local and Companyb?
Thanks in advance for the assistance. I'm really at a loss here and am not sure what to do at this point. I think it would be too much of a pain to rename the existing domain.