ADFS WAP Redirects to Backend URL on Successful Logon

Question

I have a domain mydomain.local and an ADFS Server adfs.mydomain.local. I've published by ADFS directly and also using WAP with external URL adfs.mydomain.com and backend URL adfs.mydomain.local.

When I access the application, I get ADFS Web Form adfs.mydomain.com, once I enter the credentials I am redirected to adfs.mydomain.local which isn't accessible publicly.

Is this the expected behavior and I've to have both external and backend URL's as public names adfs.mydomain.com? or Is there any configuration changes that has to be made for it to work?