Which protocols can be used to access a Junos OS device via J-Web?

J-Web is the web-based management interface for Junos OS devices, providing an intuitive GUI for configuration and monitoring. The protocols that facilitate access to J-Web are HTTP and HTTPS.

HTTP is used for accessing web pages, allowing users to connect to the J-Web interface without encryption. However, HTTP is not secure, so for secure communication, HTTPS is employed. HTTPS uses SSL/TLS to encrypt the data exchanged between the client and the server, providing a secure way to manage devices without exposing sensitive information.

The other options involve protocols that do not relate directly to web-based management. FTP and SFTP are used for transferring files, while Telnet and SSH are command-line protocols for accessing the device's CLI rather than J-Web. RDP and VPN are also unrelated to the J-Web interface as RDP is primarily for remote desktop access and VPN is for creating secure connections between networks. Thus, the most relevant and correct answer for accessing J-Web is through HTTP and HTTPS.