tq-013-traceroute-with-payload.md

tq-013 traceroute with payload

If a TCP¹ or UDP² request triggers an unexpected response it is interesting to do a traceroute with that payload to understand if we can point to a network location possibly responsible for the unexpected response. It is also interesting to compare the result of the experiment to an ordinary traceroute without payload. A UDP experiment should account for multi-path and perform several experiments following the logic of paris-traceroute³. A TCP experiment can’t do that without root as it’s impossible to stick to the path (reuse 5-tuple) within reasonable timeframe as it requires to wait for TIME_WAIT timeout (order of minutes) before performing the next experiment.

1: DNS/TCP, TLS Client Hello, Tor/TLS, HTTP GET, OpenVPN/TCP and so on

2: DNS/UDP, OpenVPN/UDP

3: TBD: does dublin-traceroute provide any useful extension above paris-traceroute?

TBD: does IP_RECVERR + IP_TTL provide enough information for TCP sockets