In a Microsoft Exchange Server 2007 organization, a computer that is running Exchange 2007 that has the Client Access Server role installed can act as a proxy for other Client Access Servers wit...
Updated Jul 01, 2019
Version 2.0
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Hey Adam,
Yes, CAS-CAS Proxy is done via HTTPS. The article you are referencing is a bit old and I vaguely recall that it may have been accurate at that time but everything is 'secure by default' now. I'll try to get the article updated ASAP.
In regards to installing public certificates, this isn't required for proof of concept installations or initial deployments. However, you'll want to review some of the excellent blog posts on the subject and plan accordingly. There are several links about
this referenced above.
The article you reference does include some optional configurations on how certs are used, so you aren't stuck with the default configuration although I highly recomend that you don't stray too far from it. There's also this, but it's a little short on details
but it's a good overview:
Understanding Proxying and Redirection
https://technet.microsoft.com/en-us/library/bb310763.aspx