Traceroute maps the path packets take across IP networks by exploiting the Time-To-Live (TTL) mechanism. By sending packets with incrementally increasing TTL values, it triggers ICMP Time Exceeded messages from intermediate routers, revealing each hop. The article explains ICMP fundamentals, packet formats, different probe methods (ICMP, UDP, TCP), and provides a complete Go implementation using raw sockets. The tutorial covers crafting ICMP Echo Requests, validating replies, calculating round-trip times, and interpreting results, while noting that production tools would benefit from features like reverse DNS lookup, ASN identification, and concurrent probing.