You can require a certificate from any clients that your communication with your server. This ensures that you trust the client and enables the client to communicate freely with your server. This is then peer-to-peer communication rather than client/server communication
To request or require a certificate from clients who communicate with your server:
If the CA who signed the client's certificate is not trusted, communication is prevented. If you want to trust the signing CA, you can add it to your trusted CAs by updating the relevant certificates options in your browser.