A growing number of contemporary Web services are hosted on SNI servers. SNI servers are virtual environments where one server hosts many web sites each of which has a different TLS certificate. The server itself presents a single IP address to other systems.
In order to connect to a specific Web service, the client must present the hostname it is attempting to connect to the SNI server. This is done thanks to the SNI extension to TLS and a TLS request (handshake) from the client includes the hostname. The SNI server includes a database with a list of all certificates and selects the respective private key and certificate.
SNI was created as a solution to the IPv4 addresses shortage and mostly affects legacy services. If the host provider moves a service to a SNI-enabled server, and the Web service and the client do not support SNI, clients can lose connectivity.
Micro Focus supports the Server Name Identification (SNI) protocol from version 5.0 Patch Update 1 of the product. You must have this version or later installed in order to avoid issues with clients trying to connect to SNI servers.