Exchange 2013 HA With tow servers

Hi all, I will implement Exchange 2013 email infrastructure.

I have two Data Centers directly connected With 10Gb of bandwidth.

I need to mount an Exchange 2013 infrastructure in HA, but only two servers.

I thought mount two servers with DAG and the two roles (FE and BE).

Users accessing externally use a unique name with two DNS pesos (mail.consotos.com), if the first DNS does not work, solve the second, which will be in another data center.
What for it would need two public IPs?

What is not as do the HA for client connections internally. Is it by DNS? How do you do it?

regards

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Microsoft Certified IT Professional Server Administrator