Troubleshooting Tip: Impossible to visit a website by entering the IP address of website but possible to visit website by entering the hostname of this website

Solution:

1. Use nslookup in the host machine to verify that the DNS resolution of the website is working.
2. Ping the hostname of the website from the host machine to verify connectivity.
3. Visit the website by entering its URL, the website will load.
4. Visit the website by entering its IP, the website will not load.
5. The website server is configured to respond only to requests based on hostname. This is not a FortiGate issue.

Most of the Websites these days are behind a Reverse Web Proxy. This allows to conserve public IP space, as it's possible to host multiple Websites under a single public IP.

For the Reverse Web Proxy to analyze which Website the client wants to connect to, it will need to check the SNI on the Client Hello. This is why it will not work by using the IP address, and only work with FQDN.