I have a customer with SBS 2011 and the Exchange server is configured to accept external mail to two domains within the organisation, domain.com and domain.co.uk which works fine no problem.
When I create a distribution group called Sales the default domain email address is registered to the group which is the .co.uk domain. any external mail sent to sales@ domain.co.uk are happily accepted and forwarded to the appropriate user members. Using EMC I added the domain.com address to the distribution group. If an external email is sent to firstname.lastname@example.org the mail is bounced as the address is not recognized at the organisation .
Please could anyone let me know how I configure the Sales distribution group to accept external mail for both domains so that external emails sent to Sales@domain.co.uk and email@example.com are accepted and forwarded to the appropriate user members.