I'm currently migrating AD Forest/Org A with mixed E2K3 (SP2) & E2K7 (SP1) into Separate AD Forest/Org B with E2013 SP1. Most all MBs are still on 2K3. SMTP Domain will not change so this will be a 'shared namespace' scenario. Note that the new AD/Exch is a greenfield and trusts have been created/validated and DNS resolution via 2ndary zones on each side is working.
I’ve searched/dug reviewed and found all of the 2003-2013 KBs for handling the shared namespace but I think my scenario is not ‘standard’ because of the mixed source environment (maybe…)
SOURCE:
4 E2K3 servers – not true FE/BE config.
2 E2K7 Servers (1 CAS, 1 MBX)
TARGET:
2 2013 CAS Servers – DNS Round Robin
4 2013 MBX Servers
Mail flow from 2013 to source org MBs (both 2K3 & 2K7) works fine via 'accepted domain', send connectors, etc. However, my problem is with flow from 2K3/2K7 into 2013 target org. When I reply back to the 2013 MB (or send to another known good in 2013), I get the 5.1.1 ‘e-mail account does not exist…’ NDR.
I've modded the 2003 default recipient policy to make the shared namespace nonauthoritative for source org, assigned another domain as authoritative, & created the SMTP connector to 2013 for the shared domain namespace. I also reset the shared namespace as the Primary SMTP in the default recipient policy due to the requirement that all new & existing users continue to be able to send/receive with our internet domain.
However, despite the org-level changes in 2K3, in 2K7 the shared namespace still shows up as authoritative. Next, when I change the shared domain in 2K7 from authoritative to internal relay, the queues start filling up (either via the SMTP connector to 2013 or the outgoing internet queue). Changing things back in 2K7 to authoritative allows the queues to empty out and mail to be delivered again. Also, when I change the domain setting back in 2K7, the domain settings on the 2K3 recipient policies are reset back to authoritative as well!
How do I handle this mixed/inconsistent configuration in my source/legacy environment? Recipient policies have not been upgraded in the legacy environment to E2K7 yet, BTW. Do I need to change things in both 2K3/7, or only manage things from one side? If so, what and/or which one? Since mail is being sent from 2013 into 2K3 (per the send connector) and arriving in both 2K3 & 2K7 mailboxes, is this even the issue? I’m not sure where to go with this.
Thanks
John