How to Send Required SNI Information to Servers on IIS or Linux Based Servers?
About
What is SNI?
SNI (Server Name Indication) is an extension of the TLS protocol that allows a client (e.g., a web browser) to indicate which hostname it wants to access when connecting to a server. SNI is essential for servers hosting multiple websites with multiple SSL/TLS certificates on a single IP address—a practice often referred to as virtual hosting.
Without SNI, the server cannot determine which website the client wants to connect to until after the connection is established, making it impossible to present the correct certificate. With SNI, the server knows which hostname the client intends to connect to and uses the appropriate SSL/TLS certificate to establish a secure connection. This is especially important in scenarios where a server hosts multiple websites, as the server needs to identify which web service the client is trying to access.
On servers (Backend Services) where SNI information is mandatory, it must also be configured on TR7 ASP.
Interface
SNI
Step > 1
Follow the steps "Traffic Manager > Backend Services" to open the edit form for the relevant Backend Service or to add a new Backend Service.
In the opened screen, after enabling the SSL Service, enter the SNI information. If the SNI information used to connect to the relevant Backend Service is unknown or there are multiple SNI entries, click the "fx" button. In the window that appears, select the Host Header Information variable and click "Submit".
Through the variable check, the request made to the relevant service with the specified HTTP Host header information ensures that the request to the Backend Service is made with the corresponding SNI information.
