VMware Tools contains a utility that allows
the NSX-V Manager to collect the IP address(es) of each guest running
in the cluster. NSX-V Manager uses the IP address as a match criterion
to steer traffic to the VM-Series firewall. If you do not have VMware
tools installed on each guest, the IP address(es) of the guest is
unavailable to the NSX-V Manager and traffic cannot be steered to
the VM-Series firewall.