Information
Disable the autoexpand option for vDS dvPortgroups.
*Rationale*
If the 'no-unused-dvports' guideline is followed, there should be only the exact number of
ports on a vDS that are actually needed. The Autoexpand feature on vDS dvPortgroups can
override that limit. The feature allows dvPortgroups to automatically add 10 virtual
distributed switch ports to a dvPortgroup that has run out of available ports. The risk is
that maliciously or inadvertently, a virtual machine that is not supposed to be part of that
portgroup is able to affect confidentiality, integrity or authenticity of data of other virtual
machines on that portgroup. To reduce the risk of inappropriate dvPortgroup access, the
autoexpand option on VDS should be disabled. By default the option is disabled, but regular
monitoring should be implemented to verify this has not been changed.
NOTE: Nessus has not performed this check. Please review the benchmark to ensure target compliance.
Solution
1. Connect to the vCenter Server using the Web Client.
2. Open the settings for Networking > (vDS name) > (dvPortgroup name) > Manage >
Edit Settings > General
3. Configure 'Port allocation' to 'Fixed'.
4. Configure the 'Number of Ports' to the exact amount required for legitimate virtual
machine connections to that dvPortgroup.
Default Value-The default state is the prescribed state.