ok, so i have successfully migrated all of our US employees from Exchange 2010 to 2013 cross forest on prem.
we are all happy that it is done!! WOot WOot...
so now i am thinking post-migration task.
to give a bit of background, US & UK were 1 company, then there was a split & now we are 2 separate companies. The Uk people are still using Exchange 2010 & the old domain (company.local) & will continue to. All of us US employees are now on exchange 2013 in a separate forest (company.US,, there is a 2 way trust in place) Currently all of our PC's are still part of the .local domain & thats how we login, however Lync & Exchange use our new .US accounts (domain migration is happening in a few weeks)
so on the .local side, any migrated email accounts, have been converted from mailboxes to contacts/mailusers, with external addresses that point to our new email domain. (via x500 emails/forwarders)
I being a bit green to some things x500, i am not sure what this does, except possibly tell the outlook client that the MB doesnt exist in .local anymore & is over in .US (like i said i am not 100% on this) Which then is the reason that the outlook clients get the initial pop up stating your admin has made a change & you need to restart outlook. However there is also a corresponding X500 email listed for the users in the .US side (not sure what that is for, unless that is how exchangematches the .local to the .US account)
My first question is, what happens for users who are still using domain accounts on .local, but email from .US via Outlook if & when the x500's are removed. Will outlook continue to work? or would we need to go into outlook & remove everyones account , & then put in the new .US account. (right now the outlook clients still show the old email address. John.smith@company.com. The new address is John.smith@companyUSA.com)
Or is the outlook client already looking at the new .US server & no longer @ the old UK servers?
also, we have noticed some issues with Full access & send-as permissions. The user & corresponding groups have been granted full access & send-as via the shell, however they would get odd """T
his message could not be sent. Try sending the message again later, or contact your network administrator. Error is [0x80070005-00000000-00000000].""""
& would get emails bounced back when trying to send as the other account. Groups & permissions & everything were checked & nothing seemed to work. Until i then took the users AD account from the .local side, & added it to the Group that has full access/send as on the .US side. Keep in mind that the Exchange account was/is already a .US account, but the domain account is .local & Outlook still says company.com instead of companyusa.com (mail to the main mailbox flowed fine, in & out, outbound even comes out as CompanyUSA.com. So it seems that outlook is still using the Domain account & not the exchange account to determine some rights.
Obviously this second item ^^ we hope to be fixed once the domain migration is finished.
So for the most part i want to know about the x500, & if when we are all using domain & email accounts on .US, & then the UK removes/deletes our accounts from .Local.
the reason i worry, is i have seen people post about issues post migration after they turn off the old exchange servers.