How do I set up a connection to Exchange from the inside using an external certificate?

Question

Microsoft Exchange

There is the following structure: the local office network is connected via an EoIP tunnel to the data center, where the Exchange server and the domain controller serving the mailer and the office network are located. Previously, the Exchange server used a self-signed certificate, with all the accompanying disadvantages. Recently faced with the fact that Apple technology does not accept self-signed certificates for mail, and it was decided to replace the certificate with a normal one from let's Encrypt. The certificate was replaced, everything is in order from the outside, but on the Outlook clients inside the network, when turned on, a message began to appear about the discrepancy between the actual name and the certificate. Annoys users and interferes with work. Accordingly, the question is how to make sure that clients from inside the network use the same certificate as those who are outside?

Answer 1

splitDNS. Make the same zone inside, i.e. configure dns so that end devices connect to the same endpoint.
Then you can use the script so you don't miss anything:
https://practical365.com/exchange-server/powershel...