In Adaxes 2017.2 and earlier each instance of Adaxes Web Interface had its own configuration that was stored on the computer where the Web Interface was installed. As a result, you could have Adaxes Web Interface installed on different computers having Web Interfaces with the same names and different configurations.
Starting with Adaxes 2018.1, the Web Interface configuration is stored on Adaxes backend together with the service configuration. As a result, you can have only one Web Interface with a unique name. There is no possibility to create Web Interfaces with same names no matter how many instances of Adaxes Web Interface you have installed.
That is why, you will need to create two Web Interfaces with different names. One will be available only on the computer in the DMZ and have Auto Logon disabled, the other will be available only on internal computers and will have Auto Logon enabled.