On Cisco devices, the `traceroute` command works by sending UDP (User Datagram Protocol) packets to destination ports that are unlikely to be in use (typically starting at port 33434). Here’s what happens step-by-step: 1. Traceroute sends UDP packets with a small Time-To-Live (TTL) value. 2. Each router that receives the packet decrements the TTL by 1. When it reaches zero, that router drops the packet and sends back an ICMP Time Exceeded message to the sender. 3. Cisco devices use these ICMP re