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RIPE-NCC / ripe-atlas-probe-measurements

RIPE Atlas probe measurement source code
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The problem of paris traceroute in TCP #8

Open xhdix opened 2 years ago

xhdix commented 2 years ago

Measurement: 39288974 Probe: 1002641

In paris traceroute mode, there are usually two duplicate hop:

image

I do not know how this can happen. (I have not read the code yet)

you can see it in all measurement of probe 1002641 on 2022-03-10:

image

all of which were in paris traceroute mode:

image

PhilipHomburg commented 2 years ago

Random question, is it possible that there are actually two nodes that have the same IP address? Your traceroute has a lot of RFC 1918 address and an IPv4 link local. All of those are not guaranteed to be unique.

xhdix commented 2 years ago

I don't think so. There is no same IP address in standard traceroute and RTTs are also the same. (Although, the first RTT is a bit strange.) Also, they doing static routing.

image

https://atlas.ripe.net/measurements/39537917/#probes

PhilipHomburg commented 2 years ago

Ah. I see. It is possible that the packets of two measurements got mixed up.

xhdix commented 2 years ago

So this can also happen in standard traceroute?

PhilipHomburg commented 2 years ago

Hard to say. Paris traceroute and standard traceroute have a different way of storing parameters in packets