A trusted site is a website that you trust not to damage your computer.
If you set the security level of your Internet Explorer® browser to High, so that you do not access websites that might damage your computer, you may be unable to access a specific website that you trust. To access the website, you can add the URL of the website to your Trusted Sites list or change your security level to Medium or lower. When using a high security level, you need to add the Web application URLs to your Trusted Sites list.
NOTE: If you are running Windows Vista, you must add the site with both "http" and "https." Also, trusted sites may open in a new browser window.
NOTE: If you are running Windows Vista, verify that Enable Protected Mode is NOT selected.
NOTE: Mozilla Firefox® does not specifically offer a trusted sites setting. However, you can set allowed sites for the limited purpose of installing cookies and add-ons. From the Tools menu, select Options and go to the Security tab.