I have an exchange 2007 server, it is a single server that is installed with hub, client access, & edge roles in one box. Now what has happened is that we've purchased another company and we need to merge their domain into our exchange server. This isn't a big deal since they just used pop and pst files. So i created the users in AD and they have their new email addresses. Then i added their old email addresses to their accounts. So the users should be good to go. Now to setup the exchange server, under "Organization Configuration" -> Hub Transport, under the accepted domains i added the domain under here as an Authoritative domain. Same as another one of our secondary email domains. I then had them change the dns mail pointer to our domain (actually i had them do this first but...). So now if I ping the new mail record the dns has changed (its been 60 hours at least as well). Now when I email from the outside I get an NDR: This system is not configured to relay mail from <outside@outside_email_address.com> to <info@new_exchange_email_domain.com> for 10.150.174.2. Note: The IP is always the sending server. Now I've tried this from gmail, hotmail and a few other external domains and I get the same message. To me it looks like exchange thinks it should be relaying this domain and not accepting this. I think i'm missing a step here, but don't know what it is. Any incite on what i need to try? Thanks,

Figured it out. Exchange was configured fine, the spam filter (external) was not. Once I put the new domain on the accepted list for the spam filter, it works like a charm.