Using Round Robin DNS between two different mail systems and not all the same user accounts
Posted on 2011-03-18
Here is my situation. I am trying to set up Google Apps for Education for a client. The apps part is all done except for the Gmail portion. I'm trying to do this a little different than the Google recommended method. I know someone who has done this, he's just not sure how he set it up to work on both system, they switched to straight Gmail.
Here is the scenario. I have a Groupwise server with admin, staff, and faculty. In Gmail I have some staff members and students. The staff members in Gmail are also on the Groupwise server. The users on Gmail will no longer use Groupwise, but the accounts will still be there for Groupwise members to communicate with. In the Gmail client, we IMAP the Groupwise server and use a fake pop mail account with the actual pop server name. This way, Gmail picks up all of the messages for that user and syncs them up. My problem is getting a round robin DNS structure with the MX records that works correctly. Previous attempts have had some mail bounced by the Gmail server because I wasn't doing the records correctly. I would like to see if this round robin structure is likely to succeed or am I going about it wrong. I've done this on Exchange before but never two totally different servers and different users in the same domain. Here it is:
1 ourdomain.s10a1.psmtp.com (gmail postini spam server)
5 barracuda.ourdomain.com (gateway to Groupwise server)
5 aspmx.l.google.com (Google mail server)
If I understand Postini correctly, all mail is directed to them first and them I want it to find the appropriate server for delivery. So a Groupwise users mail goes to Postini, then Postini asks both Gmail server and Groupwise server if the user is valid and always give Groupwise mail to Groupwise (Gmail users can pick up mail from either server) and not bounce the message if Gmail server doesn't have that user. I appreciate any and all imput.