One of the things I like about VMWare ESX is the security in their Layer 2 Virtual Swicthes. They will not permit them be joined together so loops is not an issue and they let you apply 3 policy settings to secure the vSwitches this are:
This settings will prevent the virtual machines that use the switch from acting as a sniffer, changing their mac address or forging traffic with fake mac address thous protecting the rest of the virtual machines in the case of a compromise of a VM from it being used to conduct Man In the Middle Attacks, ARP Poison Attacks or being used to sniff traffic. To set the Policy on Reject on a virtual switch it can be done both from the Service Console or thru the VI Client. On the VI Client:
- Log into the VMware VI Client and select the server from the inventory panel.The hardware configuration page for this server appears.
- Click the Configuration tab, and click Networking.
- Click Properties for the vSwitch whose Layer 2 Security policy you want to edit.
- In the Properties dialog box for the vSwitch, click the Ports tab.
- Select the vSwitch item and click Edit.
- In the Properties dialog box for the vSwitch, click the Security tab.
- Select reject on the drpdown boxes for all 3 Policy Exceptions.
- Click OK
From the CLI just SSH into the Server and su to have root privilege and run
- vmware-vim-cmd hostsvc/net/vswitch_setpolicy --securepolicy-macchange=false
- vmware-vim-cmd hostsvc/net/vswitch_setpolicy --securepolicy-forgedxmit=false
Promiscuous is already set to reject by default.