Access user account by IP + username or similar

I have Virtualmin 3.93 installed, but I need to know how to access a users account by IP + some kind of username or whatever. In cPanel this would typically be, what is the equivalent in Virtualmin?

I know how to set up a default site for the IP, but I need my users to be able to check their own content when upgrading, changing hosts etc, so they have to be able to access a useraccount before I do the DNS switch.


There’s some details on how to do that in the first section here: