Title: Require Visitor to Enter Name When Commenting
A "Visitor" is a user who can access your server, but has not logged in. If the Visitor account is given comment permissions, the Visitor will be have the option to include their Name and Email address. (note, however, all comments made by a Visitor will show as Authored by "Visitor" - the Name and E-mail address information will appear in the comment footer).
When this setting, "Required Visitor to Enter Name When Commenting" is set to "yes," the user will have to provide a value in the Name field.
There is, of course, no assurance that people commenting on your server as Visitor will enter their real names, but this does provide a way to require it.