Hello, Thanks for the hard work and understanding, and the teaching about this kind of information that complement the understanding of the solution/answer given. i understand and found (is) valid the quick response that you found and show me. So to put it simple, if i am using NetworkManager, to disable IPv6 or any related to interface params, have to use NetworkManager, because at boot and in other init, it will overwrite/enforce they configuration. thank you very much for you time team.