In my scenario we have four branch offices and head office with different domains and different email address as below
User1@ Branchoffice1.com> using Exchange 2010
User2@ Branchoffice2.com > using Exchange 2010
User3@ Branchoffice3.com >using Exchange 2013
User4@ Branchoffice4.com> using Exchange 2010
User5@Headoffice.com> using Exchange 2010
According to management decision, I need to work to consolidate email address for branch office, meaning that all branch office users will get headoffice.com email address so that they can use both internal and external email address as headoffice.com instead of branchoffice.com.
At present, management do not want to move mailbox from branch office to head office rather only email flow so that all branch office users will send and receive email via headoffice.com sitting in their own email infrastructure.
Branch offices users will be using branch office exchange sever for their active directory and exchange authentication but their email address will be headoffice.com instead of branch office.com. And we are not planning to move branch office user’s mailbox to head office.
I am ok with the technical configuration for the above requirement and followed the procedure as Simon advised.
Now I need to know how I can ensure DR site redundancy for incoming e-mail. Since all the branch offices incoming emails will be receiving through head office and if head office primary site goes down then it will impact head office & branch office incoming email directly.
In the head office we have Disaster Recovery site, where by I have configured one Mailbox server which is member of the DAG, Hub transport server, CAS server. We have iron port in the primary site but do not have iron port in the DR site rather I have configured one EDGE server for DR site.
To ensure DR site redundancy for incoming email, should I introduce another IRON port in the DR site for SPAM filter instead of relying on EDGE server and if any disaster strikes I can make that site active?
In addition to head office DR site, should I configure one of the branch office site as DR as well meaning that I am planning to Add one more server from Branch office as a member of DAG, then another server for HUB/CAS but the branch office servers (Mailbox, HUB, CAS) will be part of head office Active directory . Please advise.
Note: I have asked kind of similar question as the URL below whereby Simon advised on the technical procedure. But now need to know the DR site redundancy for incoming e-mail.