On 08/30/2013 01:58 PM, Randy Bush wrote:
In a study using the RIPE Atlas probes, we have used a heuristic to figure out where the fragments where dropped. And from the Atlas probes where IP fragments did not arrive, there is a high likelihood the problem is with the last hop to the Atlas probe.
i wonder if this is correlated with the high number of probes being behind nats.
That would be a viable explanation, although we have not tried to fingerprint the probes to figure out if this was true. If we will rerun the experiments in the future, we should spent more effort into identifying the router/middlebox that is giving the IP fragmentation problems (drops or blocking PMTUD ICMP). -- Benno -- Benno J. Overeinder NLnet Labs http://www.nlnetlabs.nl/