VirtualBox intermittent network outages
For about a year I have had terrible problems with short but very frequent network outages between Linux guests running in VirtualBox and the world at large at a customer site. At home it works, but there the connection is lost and then restored every few minutes. Very frustrating. Today I finally found a solution. It appears that it is a known bug that goes way back, see ticket 13839. Sure enough, changing the virtual network card to PCnet-PCI II solved the issue! No more outages.