Actually I have test that with ASM (not blocking mode) , but I noticed that the public ip does not reach the backend server. Cuz the first page in app is a login page, when I try to enter my user and pass there is a message show "user name or pass not correct" this is when the public ip placed in api url . But when i replace public ip with the backend ip in api url the app works fine.
The idea from adding public ip in api url is to pass traffic through WAF and that public ip should reach the backend ip . I don't know of this the way doing that or not.
Thanks