Just shutdown the network and look for a duplicate ip address (nmap, ping or whatever). If you can't debug your network, I'm afraid I can't help too much. 127.0.0.53 is a localhost address, so you can't probably see it from inside the virtualbox machine in case you are exposing such service from the host. Probably some hacky static network rule might help, but without nmap scan logs I can't help further.
** Changed in: virtualbox (Ubuntu) Status: New => Incomplete -- You received this bug notification because you are a member of Ubuntu Bugs, which is subscribed to Ubuntu. https://bugs.launchpad.net/bugs/1632084 Title: Virtualbox not able to see network in yakkety To manage notifications about this bug go to: https://bugs.launchpad.net/ubuntu/+source/virtualbox/+bug/1632084/+subscriptions -- ubuntu-bugs mailing list ubuntu-bugs@lists.ubuntu.com https://lists.ubuntu.com/mailman/listinfo/ubuntu-bugs