My laptop running Windows 8 Pro RTM with 12GB of RAM also serves as an "ant farm" where I was testing out a set of Linux appliances. I had three virtual switches: one that shared my wireless adapter, one that shared the wired adapter, and one for the internal network. An Endian VM routed traffic between the external connections and the internal ones, and provided DHCP services to the VMs that were running. I was able to successfully use Opera and Filezilla on my laptop to get to all of the browser based and SSH services (e.g. Webmin on the LAMP appliance I was working with), and all was well.
In other words, my wireless adapter (say, 10.10.0.24/24) would provide external access to the Endian (192.168.5.1/24), which would in turn route traffic between the Wordpress appliance (192.168.5.2), the outside world (e.g. themes and updates from Wordpress.com), and my laptop itself.
One day recently, for no discernible reason, traffic stopped flowing betweem my laptop and the guests. I killed the Endian and rebuilt it, no dice. I was only able to configure it from a guest internally (where I did enable DHCP, DNS, etc.). None of the other VMs were accessible from the host, either, only from within the guest network.
DHCP Guard is off. Router Advertisement Guard is off. Endian is successfully leasing IP addresses to guests. The internal switch is explicitly an 'internal', not a 'private' one. Neither the Endian nor any other VM on the virtual LAN will respond to a ping direct from my laptop. The Endian, along with the rest of the servers, however, can successfully get to the internet.
How do I restore communication between my laptop and the virtual machines it contains?