You know how when you connect to McDonalds wifi, you go to google.com and it magically changes the page to their wifi connection page? Well hackers can do the same, by rebinding the dns and changing all pages to their ones, either phishing or just listening to all traffic. That is why you want the dns rebinding protection on at all times, and only disable it when you actually need a page to redirect to a portal, like McDonalds wifi for example.
So you get on wifi, try to connect the repeater. If you don’t get any internet, you disable the dns rebinding, connect the repeater again, and go to any page. The page will get redirected, you accept the terms, login or whatever, then disable the dns rebinding again after you have internet.