What application Layer protocol can allow Frances's private IP address to connect to a public server?

Network Address Translation (NAT) plays a crucial role in enabling a private IP address to connect to a public server. NAT is a method used by routers to translate private (non-public) IP addresses used within a local network into a single public IP address. This translation allows multiple devices on a local network to share a single public IP address for external communications.

When Frances's device, which operates on a private IP address, tries to connect to a public server, NAT modifies the outgoing packets by replacing the private IP address with the router's public IP address. When the public server responds, the NAT device recognizes that the response is meant for the private IP address and performs the reverse translation, sending the response back to Frances's device. This process allows secure and efficient communication between private networks and the broader internet.

The other protocols listed serve different purposes. For instance, Dynamic Host Configuration Protocol (DHCP) is primarily used for assigning dynamic IP addresses to devices on a network and does not facilitate connectivity to public servers. File Transfer Protocol (FTP) and Hypertext Transfer Protocol (HTTP) are application layer protocols used for transferring files and retrieving web content, respectively, but they do not handle the translation of private addresses to public addresses.