Timeline for Traceroute UDP port question

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Sep 14, 2018 at 9:19	comment	added	jonathanjo		It's just worth pointing out that the intervening routers may well not send ICMP time exceeded, and even if they do, ICMP packets are delayed or dropped at whim by many public networks. Also, as the internet routes per packet, every single one of the 3 x N hops packets might go a different route. Which is why it's very frequently said that traceroute on networks you don't know in detail are approximations at best. Also worth knowing about are the record-route IP options, which have their own problems. You're free of course to devise your own network mapping algorithms.
Nov 4, 2017 at 4:29	comment	added	user30830		I don't know why your answer was downvoted, but it really explains the reason for the UDP port incrementation. You are right, it serves as identification number for the datagram order. Initially, I thought, traceroute is waiting until the reply is received or timed out before sending out the next datagram, but after capturing mysely I can confirm, that, indeed, traceroute sends out a bulk of UDP messages without waiting for the replies to arrive, thus, it increments each UDP port with +1, so that it can later identify them, when the replies arrive, and put them to output in correct order.
Nov 4, 2017 at 4:19	vote	accept	user30830
Nov 2, 2017 at 9:58	history	answered	jcbermu	CC BY-SA 3.0