hello. in the process of deploying a (2) server Exchange 2010 environment, which will temporarily be in co-existence with 2003. Both 2010 servers will have all 3 roles (CAS, HT, Mailbox), both with be members of a CAS array and both will be configured as DAG. I will not be doing load balancing since both will be in a CAS array and a DAG and there is only 2 servers and not external hardware load balancer at this point.
I realize that all OWA traffic will route through only 1 of the 2 new servers since there is no load balancing. and I realize that i will configure my internal dns for the CAS array to point outlook client requests either to a single server (and manually update if it ever fails) or to both servers via DNS round robin.
What I want clarification on is how the mx records come into play. All inbound/outbound smtp traffic will be routed through our smarthost (sonic wall spam filtering appliance). Do i simply have a single external mx record that resolves to the sonic wall and then on the sonic wall have a rule that allows mail to/from both of the 2010 servers?
one other question - if the majority of our corporate client use is OWA on the internal network, could i also create multiple internal DNS records that point to each of the 2 servers and use DNS round robin for that traffic as well?