Yeah, and what do you do with a traceroute that looks like this…. (ip address intentionally changed) C:\>tracert -d -w 1 1.2.3.4 Tracing route to 1.2.3.4 over a maximum of 30 hops 1 8 ms 5 ms 5 ms 96.8.191.129 2 * * * Request timed out. 3 * * * Request timed out. 4 * * * Request timed out. 5 * * * Request timed out. 6 * * * Request timed out. 7 * * * Request timed out. 8 * * * Request timed out. 9 * * * Request timed out. 10 * * * Request timed out. 11 * * * Request timed out. 12 * * * Request timed out. 13 * * * Request timed out. 14 * * * Request timed out. 15 * * * Request timed out. 16 * * * Request timed out. 17 267 ms 202 ms * 1.2.3.4 18 205 ms 175 ms * 1.2.3.4 19 160 ms 233 ms * 1.2.3.4 20 199 ms 201 ms * 1.2.3.4 21 213 ms 206 ms * 1.2.3.4 22 165 ms 158 ms * 1.2.3.4 23 237 ms 158 ms * 1.2.3.4 24 158 ms 290 ms * 1.2.3.4 25 158 ms 160 ms 158 ms 1.2.3.4 Trace complete. C:\> From: NANOG [mailto:nanog-bounces@nanog.org] On Behalf Of Etienne-Victor Depasquale Sent: Thursday, December 12, 2019 1:18 AM To: Valdis Klētnieks Cc: nanog@nanog.org Subject: Re: Short-circuited traceroutes on FIOS Traceroute is becoming more and more an expert's tool because interpretation of its results isn't straightforward. I had written a paper last year and mentioned its misuse in academia in the context of estimating the number of energy-consuming devices between a source and a destination. Traceroute was being used to count the number of physical router devices from the hop count, notwithstanding the use of MPLS in domain cores. To an external observer, this results in significant underestimation of the energy consumption in the path from source to destination. On Thu, Dec 12, 2019 at 12:51 AM Valdis Klētnieks <valdis.kletnieks@vt.edu> wrote: On Wed, 11 Dec 2019 19:26:09 +0200, Saku Ytti said:
On Wed, 11 Dec 2019 at 19:14, Rob Foehl <rwf@loonybin.net> wrote:
Support claims that it was a mistake, but it's also been 15+ months and it's pretty deliberate behavior. Draw your own conclusions...
TTL decrement issues are fairly common across multiple vendors and hw, can be sw can be hw limit
Yes, but you need to screw up gloriously on the decrement if you think that "I decremented and it's zero now" means "therefor it must have been addressed to me, so I'll send an ECHO REPLY instead of TTL EXCEEDED". -- Ing. Etienne-Victor Depasquale Assistant Lecturer Department of Communications & Computer Engineering Faculty of Information & Communication Technology University of Malta Web. https://www.um.edu.mt/profile/etiennedepasquale