the company i work for has two domains ill refer to them as company.net and company.org. In our office we host the company.org Exchange server. Our ISP hosts a company.net and company.org which reside on the same server, I believe they are using qmail for their server. when sending email from company.net to company.org the email bounces back saying something along the lines of account not found. even though the account does exist on the exchange server at my office. the only workaround is that we add the same account to company.org at the ISP. shouldn't the emails be coming to company.org at the office first? this is the only domain that we have problems with. our exchange server at the office is used for correspondance everyday with many different domains, and none fail. the only conclusion that i could come to was that the company.org at the ISP is acting like a domain controller and would have to mirror the user accounts at my office. we also use the company.org email account as a fall back with a GFI pop2exchange connector, in case our link goes down. the only fix that i could think of was to move the company.org domain off the same box as the company.net is being hosted on. is this the right move? we want to fix this problem of not being able to send email between the domains and still keep our fault tolerance plan. thanks in advance for any responses.