At my college we have a hybrid e-mail infrastructure. Faculty and Staff on Exchange 5.5, preparing to migrate to Exchange 2000 using the move mailbox method, on another server. Students are on a UNIX SendMail server. E-mail from the Internet is routed through a UNIX SendMail hub (mail.keene.edu). Mail is checked against an alias table for username@servername and then forwarded to the appropriate server. In order to work with Exchange I had to add a secondary SMTP address for each user, i.e. firstname.lastname@example.org, with the primary (and reply) address being email@example.com. Without that secondary SMTP address, mail would bounce because the UNIX SendMail server appends the server name to the address when it forwards it on.
When I introduced the Exchange 2000 server and joined the Exchange 5.5 organization, I moved a test mailbox to the E2k server and tried to send a test message to a user on the 5.5 server. It bounced because the user was not recognized. Turns out you can’t have an SMTP address that is the same as the FQDN of the server. Easy – just strip out the secondary SMTP address. Not easy – if I do, in our infrastructure, all inbound mail will bounce because SendMail is set up to append the servername to the address.
Do any of you have a situation where you have an Exchange organization routing mail to or from a SendMail hub? How can SendMail be configured to route mail to teh proper server without appending the servername.
And, yes, I know I should never have allowed the SMTP address to be the same as the FQDN of the server.