After going over the documentation and reviewing the log a few times, and a little trial and error - this is what I came up with, and this is what is working for me:
mail.example.com {
reverse_proxy https://192.168.1.230 {
transport http {
tls_server_name mail.example.com
}
header_up Host {upstream_hostport}
header_up X-Forwarded-Host {host}
}
}
Almost like I know what I am doing, haha NOT!
I have to compliment the developers of Caddy, this has been less of a learning curve than other apps, and I am NOT a developer, my day job is infrastructure/network guy, so I am way out of my wheelhouse with this stuff. Thanks for all the help on this!