There are several limitations that need to be considered when running the Network Security Toolkit under VMware Server or VMware Player. These limitations include:
You can not directly access the hard disk of the host system. For example, you will not be able to create/modify the partition table of the host system.
You can not access files on the host system outside of the virtual machine, unless you are using VMware Workstation (not free) and configure a shared folder. You can always use network shared folders and/or scp commands to transfer files between the host system and the virtual machine.
Wireless features of the Network Security Toolkit will not be usable within a virtual machine as they tend to require direct access to the wireless adapters.
USB 2.0 devices are usable from within the virtual machine, but only at USB 1.1 speeds.
Your privilege level is limited to the user level that started the Network Security Toolkit Virtual Machine. You can not do anything within the Network Security Toolkit Virtual Machine which the user account used on the host machine is not allowed to do. For example, if you are using a "Limited Account" on a Windows XP machine, you will not be able to monitor all of the ethernet traffic within the Network Security Toolkit Virtual Machine. In this case, the host operating system should limit you to monitoring the traffic which is to/from your virtual system.