ReadyNAS uses self-signed certificate. IE7 or Windows Vista will not trust this certificate unless you explicitly import this certificate by yourself. Below is brief procedure to import certificate.
First, examine the certificate. (Left click on “Certificate Error” in address bar, and click “View Certificate”.) If the certificates “Issued to:” and current IP is different, navigate FrontView/Services/Standard_FIle_protocol. Under “HTTPS” service, there is “Generate new key” button. Specify “SSL
key host” match with your ReadyNAS' IP, and click “Generate” button. And exit IE7 (to flush cache), and connect to FrontView again.
Then install certificate into IE7. Left click on “Certificate Error” in address bar of IE7, and click “View Certificate”. There is “Install Certificate..” button. Click this button to start “Certificate Import Wizard”, so follow Wizard to install certificate.
Once certificate is installed properly, you will not be warned.
Note for Vista Users: Please note that Windows Vista works different than XP. When you are using Vista, you need to specify ReadyNAS as “Trusted Zone”, otherwise you don't see “Install Certificate..” button when viewing certificate. And while walking through “Certificate Import Wizard”, you need to click “Place all certificates in the following store” radio button, and specify “Trusted Root Certification Authorities”. (If you place a certificate in your personal store, IE will not trust it.)