In some cases, you might need to alert your users to the fact that the firewall is decrypting certain web traffic and allow them to terminate sessions that they do not want inspected. With SSL Opt Out enabled, the first time a user attempts to browse to an HTTPS site or application that matches your decryption policy, the firewall displays a response page notifying the user that it will decrypt the session. Users can either click Yes to allow decryption and continue to the site or click No to opt out of decryption and terminate the session. The choice to allow decryption applies to all HTTPS sites that users try to access for the next 24 hours, after which the firewall redisplays the response page. Users who opt out of SSL decryption cannot access the requested web page, or any other HTTPS site, for the next minute. After the minute elapses, the firewall redisplays the response page the next time the users attempt to access an HTTPS site.
The firewall includes a predefined SSL Decryption Opt-out Page that you can enable. You can optionally customize the page with your own text and/or images.
Enable Users to Opt Out of SSL Decryption
(Optional) Customize the SSL Decryption Opt-out Page. Select Device > Response Pages. Select the SSL Decryption Opt-out Page link. Select the Predefined page and click Export. Using the HTML text editor of your choice, edit the page. If you want to add an image, host the image on a web server that is accessible from your end user systems. Add a line to the HTML to point to the image. For example: <img src=" Acme-logo-96x96.jpg?1382722588"/> Save the edited page with a new filename. Make sure that the page retains its UTF-8 encoding. Back on the firewall, select Device > Response Pages. Select the SSL Decryption Opt-out Page link. Click Import and then enter the path and filename in the Import File field or Browse to locate the file. (Optional) Select the virtual system on which this login page will be used from the Destination drop-down or select shared to make it available to all virtual systems. Click OK to import the file. Select the response page you just imported and click Close.
Enable SSL Decryption Opt Out. On the Device > Response Pages page, click the Disabled link. Select the Enable SSL Opt-out Page and click OK. Commit the changes.
Verify that the Opt Out page displays when you attempt to browse to a site. From a browser, go to an encrypted site that matches your decryption policy. Verify that the SSL Decryption Opt-out response page displays.

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