Hi Guys,

Fairly simple question I'm sure for most of you.

I'm a bit confused about how inbound smtp traffic from the firewall is sent to an active server in a HA scenario?

For example, say we use ARR for CAS HA, DAG's for mailbox HA and we lose server A, ARR will redirect users to server B and server B will become the active database server - however SMTP traffic from the firewall will still be hitting server A.

What solution do you recommend for ensuring inbound traffic is always directed at an active server?

The same logic applies for SMTP relays on the network which will have the same problem.

Many thanks,

Stupac86

SMTP servers are smart enough to try different servers specified by MX records, so you don't have to pass SMTP transport through a load balancer if you don't want to, just expose two transport servers to the Internet and make A and MX records for them.