I am facing the issue when I boot Guest Windows 7 inside VirtualBox and in a couple of minutes internet connection on host becomes very unstable, losing pings, then just remote addresses stop responding completely. Once I stop VirtualBox instance, everything turns back fine again.
I clearly see this issue as connected to VirtualBox, because I can turn on/off VirtualBox multiple times at once and it happens all the way I described.
I tried NAT, Host-only, Bridged, switched all firewalls off. What I found is guest OS can't ping my WiFi router that is 192.168.1.1, but pings the host OS that is 192.168.1.123.
How can I detect a clue why it can happen?