I have two separate physical sites, Site A and Site B. In site A, I have following:
- 2 CAS servers
- 2 Hub Transport servers
- 2 Mailbox servers
- 2 Edge servers
In site B, I have the following:
- 1 CAS
- 1 Hub
- 1 Mailbox
- 1 Edge
Currently everything is working out of site A. That is, all users are housed on mailboxes that are in site A and all inbound mail flow is pointing to site A. I would eventually like to be able to move some of the mailboxes to site B without causing a disruption for resliency and redundancy purposes but I am not quite sure how to go about setting this up or if it is even possible.
So far I have created an Edge subscription in site B and am able to send emails out from test accounts set up with mailboxes on the site B Mailbox server. However, I am unable to receive incoming mail messages and am confused.
So I'm thinking incoming mail messages are still being directed to site A and then they are getting stuck because there is no way to route the mail to the site B mailboxes. Is this assumption correct? I am unfamiliar with mail flow and routing so I am not really sure what I need to be looking at?
Would I add the site B hub transport to the Edge subscription in site A? Or I guess more specifically, how would I go about enabling communication and mail flow between mailboxes split up on site A and B?
Per the suggestion of @Massimo I have done some additional testing. Here is some supplemental information, I hope it helps. I can open up a new question if necessary.
I am able to telnet on port 25 to each of the Hubs from every other Hub.
After flipping mailbox database DAG to site B here are the initial results:
- I am able to send test emails internally from Site B user to site A user.
- I am unable to receive test emails internally from site A user to site B user.
- I am able to send external emails through site B Edge.
- I am unable to receive emails to site B user.
Where shoud I start looking in order to begin troubleshooting this? At this point is it safe to say there is a mail routing issue?