I've read and re-read the manual and scoured ServerFault and other sites. I just don't get it.
I've got Virtualbox running on a Mac OS X host, with two Windows Server 2008 R2 guests. Both have a single NIC running in Bridged mode connected to eth0 on the host. Both have internet access, both can ping my gateway (a separate router connected to the internet). But they can't see each other.
When I try to ping them I get destination host unreachable. I've tried manually entering an ARP entry for the MAC address of each host in the other, to no avail.
What am I doing wrong? What am I missing?