How should I move queued messages from IIS to Exchange on different servers?

Question

We currently have a company email server with Exchange, and a bulk email processing server that is using IIS SMTP. We are upgrading to a 3rd party MTA (zrinity xms) for bulk sending. I need to be able to keep sending the messages already queued for IIS when we switch to the 3rd party sofware. Can I simply move the IIS queue files to the Exchange server queue and have sending attempts begin automatically for them? If not, any suggestions on accomplishing this?

Answer 1

You should be able to move the *.eml files to the Exchange server's pickup directory. Or set the IIS SMTP service to smart host to the new MTA, assuming they (the 3rd party) allow SMTP relay from your IP address.

Answer 2

Moving the files will work. However, any email with a BCC line in the header will get sent out with the BCC intact. Some clients, such as gmail, will display the information to the recipient, thus breaking the whole point of BCC.

This happens when copying EML files to MS-SMTP (which Exchange also uses) because the BCC information is usually stripped out of the header in during the SMTP hand-off to (not from) MS-SMTP.

If that was how the messages were initially handed off, then it's possible that the EMLs you have were already broken into separate messages for each BCC, and that header was properly stripped.

Just a little gotcha to watch out for.