vSphere UI must limit the number of allowed connections.

Limiting the number of established connections is a basic denial-of-service protection and a best practice. Servers where the limit is too high or unlimited can run out of system resources and negatively affect system availability.

At the command prompt, run the following command:

# xmllint --xpath '/Server/Service/Connector[@port="${http.port}"]/@acceptCount' /usr/lib/vmware-vsphere-ui/server/conf/server.xml 

Expected result:

acceptCount="300"

If the output does not match the expected result, this is a finding.

Navigate to and open:

/usr/lib/vmware-vsphere-ui/server/conf/server.xml

Navigate to the <Connector> configured with port="${http.port}".

Add or change the following value:

acceptCount="300"

Restart the service with the following command:

# vmon-cli --restart vsphere-ui