On 03/09/2016 10:53 PM, Sam Norris wrote:
Why does Facebook spoof the source IP address of the hop before this server?
They spoof the source IP address that is performing the traceroute.
...
(31.13.28.207) 67.846 ms ae12.dr08.ash3.tfbnw.net (31.13.29.191) 68.629 ms
12 * * *
13 * * *
14 8.25.38.1 (8.25.38.1) 68.571 ms 68.718 ms 68.132 ms
15 edge-star-mini-shv-07-ash4.facebook.com (66.220.156.68) 67.903 ms 67.752
ms 68.071 ms
---
Hop 14 is the source ip of the traceroute which is forged. This essentially
makes hop 14 reply using the same ip for src and dst.
If intentional, I would speculate that this might be something to help
their support staff by giving them confirmation of where the traceroute
actually originated from in the public Internet view given that the
originator might actually be behind possibly several layers of NAT. The
two missing hops could be a marker or perhaps other info that got eaten
due to various source filters?
--
Brandon Martin
