We have an old AIX server. it is able to send email on its own to any email address. Including over the LAN to our exchange server. Recently we migrated to SBS 2008 from SBS 2003. Now I am no longer getting the email sent from the AIX box. The AIX can still send to normal internet addresses like gmail, but it is not getting delivered in exchange.
I suspect it has something to do with security, since the AIX, has no reverse pointers or any of that detailed DNS/MX stuff set up for it.