Apache Reference: mod_auth_anon, Anonymous_VerifyEmail

Anonymous_VerifyEmail

Specify Whether the Password Is Checked to Be a Valid E-mail Address
Syntax: Anonymous_VerifyEmail on|off
Example: Anonymous_VerifyEmail on
Since: Apache 1.1

When this directive is set to ``on'', the password is checked for at least one ``@'' and one ``.'' character. It encourages users to enter valid e-mail addresses.