Dou Security worked very well on my sites, but with the last version I get a lot of warnings and errors when I log in to my site. :-(
Warning: file_get_contents() [function.file-get-contents]: SSL operation failed with code 1. OpenSSL Error messages: error:14090086:SSL routines:SSL3_GET_SERVER_CERTIFICATE:certificate verify failed in /home/overvloed/domains/my_domain/public_html/wp-content/plugins/duo-wordpress/duo_wordpress.php on line 401
I looks like Duo Security developers forget that a lot of site owners use self signed certificates to encrypt there dashboard. :-(
Please fix this, e.g. with a option to switch off the SSL check.