We are migrating from Exchange 2007 to Exchange 2013 and I have some questions around the mail flow changes in 2013.
I understand that the CAS role plays a part in mail flow now. We have our 2013 CAS servers installed as a separate role.
Should we direct our internal applications to the CAS servers for SMTP mail delivery or should it be the Mailbox servers?
Should the external mail flow next hop from our SPAM firewall be the CAS servers?
Where should we apply receive connector rules, CAS or Mailbox?