Why is it not possible to establish SSL connection to IP address in Plesk if a default website is assigned?

Question

Why it is not possible to establish SSL connection to IP address if a default website is assigned on Plesk for Windows, whereas on Plesk for Linux such a behavior is possible.

Answer

IP:Port SSL binding has higher priority than Hostname:Port SSL binding.

For example, configure two websites with SSL:

1. sni.example.com with SNI (Hostname:Port) SSL binding *:443:sni.example.com and certificate cert_sni which resolves to 203.0.113.2 IP address
2. non-sni.example.com with legacy (IP:Port) SSL binding 203.0.113.1:443:* and certificate cert_non_sni

On accessing to https://sni.example.com – the certificate cert_non_sni will be provided by the IIS instead of cert_sni.

That is why Plesk does not create legacy (IP:Port) SSL binding on websites.

Additional information

Microsoft Blog: Server Name Indication (SNI) with IIS 8 (Windows Server 2012)