Which network diagnostic tool displays the path packets take between two endpoints?

The correct choice is traceroute, which is a network diagnostic tool specifically designed to display the path that packets take as they travel from a source to a destination across a network. It works by sending a series of packets with incremental Time to Live (TTL) values. Each time a packet reaches a router, the router decrements the TTL value. When the TTL reaches zero, the router drops the packet and sends back an Internet Control Message Protocol (ICMP) message to the sender. This process allows traceroute to determine each hop along the path and the time it takes for packets to travel to each hop and back.

In contrast, ifconfig is a command used to configure network interfaces and display their current configuration settings but does not show the path of packet movement. FTP, or File Transfer Protocol, is utilized for transferring files over a network and does not serve any diagnostic purpose regarding the routing of packets. Nslookup is a networking utility used for querying the Domain Name System (DNS) to obtain domain name or IP address mapping, but it does not track the route that packets take through the network. Thus, traceroute is uniquely suited for the role of mapping the route packets take between two endpoints.