traceroute: UDP, ICMP, and TCP Modes Explained
Three probe types down one four hop path, the packets on the wire for each, and the ICMP rate limit that makes a perfect path look broken.
ICMP
The protocol behind ping, traceroute and path MTU discovery. Articles tagged ICMP cover message types, rate limiting, and why filtering it breaks more than it protects.
Latest posts
Ping Timeout vs Destination Unreachable: Decoding Every Failure
Silent 100% loss and Destination Unreachable are different failures pointing at different problems. Every ping failure message decoded with live lab captures.
How Ping Works: The ICMP Echo Exchange Explained
What actually happens between typing ping and the reply line, decoded field by field on a live 3-hop Cisco lab: ICMP echo, TTL, RTT, and jitter.