[nieprophsono]

Usually all you need to do is access the main menu of a router via the login and you can figure out what IP address the specific router uses. I am not really sure on what to do when you can't access that but I usually use the universal login to the router to hack it. What you need is to know the model and make o your router and with that knowledge you can access the main menu of the router. For example mine is https://192-168-1-1ip.host/ . I used it to restore the the router to it's factory settings and manages to change the passwords and all the major important information from others