If I understand Exchange 2013 has removed the HUB server role.
Now I am not sure if the functionality of the HUB server is included in Mailbox server or in CAS server.
I mean when an email goes out or comes in to the Mailbox server what path it will take.
in Exchange 2010, all emails going out and coming in go through HUB server.
CAS server is used just to connect throughout it to read email.
Any explanation will be very much appreciated.