I have a client who has been using Exchange server 2003 with 3rd party POP3 connector to receive emails. Onternal users have internal emails hosted by Exchange whilst other colleagues who work remotely do not have themselves set up as users and use an ISP to collect emails. All internal users could send emails to the external POP3 users even though they had the same domain name (ie all @mycompany.com).
Now we have upgraded him to Exchange 2007, the external recipients emails are being rejected by Exchange 2007 because it assumes that, as they have emails ending in @mycompany.com, they are internal recipients. Therefore the emails are not sent from the network and these then bounce as the Exchange server has no record of those email addresses as they are not internal users
I have read that it is possible for more than one mail server to host emails for the same domain, but cannot make this work. I am struggling to resolve this and would appreciate any help.
Does anyone have an ideas?