Is it possible to set up preferrential IPs when in maintainance mode? I've previously worked on Prestashop and there I had the choice to set my site in offline/maintance mode and then edit one ore more IP addresses in order other people to view the sites but not the commmon users and stills no login require and no additional host file settings.

Thanks
Actually on Drupal you can create a new role and assign permission to this role to login in maintenance mode (Add permission "System > Use the site in maintenance mode").

If this is not what you want, then you can filter IP addresses on firewall /linux level. Please ask on https://serverfault.com/ if you need this kind of solution.