Enhanced Network Security has to deal with secure data communications with a longer password using different keys between MoCA 2.1 nodes compared to MoCA 1.1/MoCA 2.0 nodes, along with the ability to control data forwarding of legacy nodes to and from MoCA 2.1 nodes. It is one of the new features added to the MoCA 2.5 standard according to the Multimedia over Coax Alliance
We recommend you do not change this setting. It is enabled by default in the ECB7250 so help with the automatic connection of your older MoCA devices. It will not affect any of the other features of our device including MoCA Privacy.