We are running in a multidomain forest.
Domain root is company.com, and child domains are uk.company.com, us.company.com and aus.company.com. For Exchange, we have 3 Admin groups to mirror this, each with their own mailbox servers etc.
In the UK domain we have created a mail enabled Global security group, GroupA.
There is a server in the US that sends an email to GroupA, but the mail is never delivered to the recipients, although there is no NDR.
I have a couple of questions I was hoping someone could help me with;
a) If the server in the US sends the email to the US Exchange server, then am I correct in thinking that the US Exchange will contact the US DC about this group, and the US DC won't have any knowledge of it?
b) We have been creating mail enabled security groups in general rather than distribution groups. Is there actually any advantage to creating distribution groups?
c) Am I correct in thinking that we should generally create global groups unless there is a requirement for the groups to be used in the other domains? Universal groups create extra replication traffic?
Urgent, so max points.