This article applies to the Barracuda Load Balancer ADC version 5.1 and above.
The Instant SSL Service allows clients to talk to the service using HTTPS while the Barracuda Load Balancer ADC talks to the server using HTTP.
In the Instant SSL service settings, you must specify at least one secured site domain whose links must be converted from HTTP to HTTPS. When the redirect service receives a request for the specified domain, it forwards the request to the service on port 443 (HTTPS), which then forwards the request to the servers. In any response, the HTTPS service rewrites HTTP requests to HTTPS requests. For example, an incoming request for is rewritten as https://www.barracuda.com/ in the outgoing response.
The service also provides an additional rewrite option named SharePoint Rewrite Support for Microsoft® SharePoint applications. Normally, an Instant SSL Service rewrites the HTTP links in responses to HTTPS using HTML tags, like href. However, SharePoint applications also insert hyperlinks outside the basic HTML tags. You can enable SharePoint Rewrite Support to ensure that HTTP links outside HTML tags are also properly rewritten to HTTPS.