Hi,
I need some help conceptualizing something that is puzzling me currently..
Basic scenario we have is
Company A, Company B and Company C are "merging" (for want of a better word)
The objective is to have a common "shared mail domain" e.g. newsmtpdomain.com that we will/should all be able to SendAs and receive mail to.
There are lots of examples, of achieving mail domain sharing (routing) between two Exchange organizations.. by setting up the primarySMTP domain as "InternalRelay" on both Exchange Organizations and then introducing a SendConnector to the"other" one .. so any mail not destined for a "local" recipient on the "first Exchange organization" (whichever that is) .. the mail would then be delivered to the other Exchange organization for delivery.
However.. is it possible to utilize a similar approach to be able to route mail between the 3 Exchange organizations ?
I'm thinking along the lines of mail arrives at Company A's Exchange org... and it maybe has two send connectors.. one to Company B Exchange Org.. and one to Company C Exchange Org.. and a mail arrives for someone at Company C... Company A exchange server will know that the user is not local.. so try SendConnector for Company B... if Company B does not allow relay (as the user is unknown there too...) then Company A SendConnector to Company C is utilized ... and Company C .. knows about the local user there and accepts delivery..
Failing the above possibility my other idea is to have a mixture of mailboxes (local users), contacts/mail-enabled users (users in the other two Exchange organization) in all three Exchange organizations .. with targetAddresses set to a subdomain of the newsmtpdomain... and then route the incoming mail around.. dependent upon the new subdomain SMTP addresses.. but for this I obviously need good dirsync between all three environments.. .. what would peoples opinions be on MS Federation gateway service.. to provide this ?? (sync'd contact lis...) etc ?
any thoughts/tips .. would be most welcome.. (of yeah I forgot to mention) all three Exchange environments are different vers of Exc. we have Company A on 2010 SP3, Company B on 2013 and Company C on 2016 (not sure that would make much difference in the proposed solution ?)
Steve Morris