Understanding Traceroute

3 days ago

Traceroute works by exploiting the TTL (Time To Live) field in IP packets to trace the route to a destination.
It sends UDP packets with increasing TTL values, starting at 1, to trigger ICMP 'Time Exceeded' replies from each hop.
The implementation involves creating sockets for sending UDP packets and receiving ICMP replies, with raw sockets requiring root privileges.
Key improvements include checking ICMP types to know when the destination is reached, adding timing for round-trip latency, and sending multiple probes per hop for reliability.
Limitations of traceroute include asymmetric paths, hidden MPLS tunnels, load balancers, and ICMP rate limiting that can cause '*' in output.

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