The secure part of INFN's web sites uses a security certificate from INFN CA.
If and when you encounter a warning from your web browser, you can confirm the security exception and proceed.
Specific instructions on how to do this in Firefox and Internet Explorer can be found below. While we can not provide instructions for every version of every browser, this information should allow you to proceed to the secure portions of the sites.
When you see a warning message like this:
If you are using Internet Explorer 7 (or 8) the warning message will look like this:
In order to avoid annoying warning messages when connecting to an INFN's secure page,
you should install the INFN certificate, following the instructions on this page.