Keep your modem! Otherwise no internet ... Well yes ...
And 2/5 because after two hours of use I can not access the router configuration portal or by 10.0.0.1, either by routerlogin.net. My browser return me "The Google Chrome attempt to connect to 10.0.0.1 was rejected. It is possible that the website is blocked or that your network is not configured properly." While it worked very well for 5 minutes before.
Anyway, I guess it is resolved with a quick hard reset, but not for me, sharing product!
Thankfully Amazon is irreproachable on this point