Over at SearchServerVirtualization.com, Chris Wolf compares the free server virtualization products — VMware Server, Microsoft Virtual Server, and XenSource XenExpress- with regard to security of their virtual switch implementations. The conclusion? Only one of the tested products featured virtual switches that offer the full isolation of a hardware layer 2 switch. Which one? Guess. Hint: I’m posting it here, and my title has “marketing” in it.

(And, of course, since they’re the same binary, his comments about XenExpress also apply to XenServer and XenEnterprise.)