3 ms·

Interesting that you can traceroute up to the destination. Over the years I have got accustomed that it's not possible any more in most cases. Some router is no

Interesting that you can traceroute up to the destination. Over the years I have got accustomed that it's not possible any more in most cases. Some router is not sending or dropping the ICMP packets I guess. Not sure for what reason. To save the load? To stop people (competitors) spying on them? news.ycombinator.com is no exception that it doesn't work: 5 a9k2-49-infra-dc2.dc3.poneytelecom.eu (195.154.1.118) 0.745 ms 195.154.1.188 (195.154.1.188) 0.865 ms a9k2-49-infra-dc2.dc3.poneytelecom.eu (195.154.1.118) 0.720 ms 6 lag-110.ear3.Paris1.Level3.net (212.3.235.197) 0.940 ms ae53.edge7.Paris1.Level3.net (212.3.235.201) 9.700 ms lag-110.ear3.Paris1.Level3.net (212.3.235.197) 0.955 ms 7 ae-0-11.bar1.SanDiego1.Level3.net (4.69.146.65) 139.415 ms 139.085 ms 139.031 ms 8 GIGLINX-INC.bar1.SanDiego1.Level3.net (4.16.105.98) 150.362 ms M5-HOSTING.bar1.SanDiego1.Level3.net (4.16.110.170) 140.286 ms 139.842ms 9 * * * 10 * * * 11 * * * 12 * * * 13 * * * (sorry, somewhat poor formatting caused by typing on the phone?)

usr1106 6y ago
Same using tracepath from another country 6: ae65.edge1.Stockholm1.Level3.net 35.147ms asymm 7 7: ae-0-11.bar1.SanDiego1.Level3.net 457.605ms asymm 16 8: M5-HOSTING.bar1.SanDiego1.Level3.net 199.025ms asymm 17 9: no reply 10: no reply 11: no reply 12: no reply
usr1106 6y ago
found the answer -M icmp
Sesse__ 6y ago
Forwarding packets happens in ASICs, generating ICMPs is usually done by the CPU (which has a packet rate of maybe 1/100000th of the ASICs). So the latter is usually either rate-limited or turned off entirely, or you could bring the router to its knees by just spamming packets with too short TTL. It's also not uncommon that people turn it off to reduce external insight into their network, for whatever reason.
- usr1106 6y ago
  Right, but the weird thing was that grand parent got a full trace up to the target and I didn't as usual. By experimenting a bit I found that when sending UDP packets the traceroute is incomplete, but when sending ICMP also my traceroute is complete. Explains how the grandparent could present a full traceroute. I had just taken it as a fact that full traceroutes are rarely possible these days. For reasons like you say, it's overhead for them and they don't want you to do it.

usr1106 6y ago

Same using tracepath from another country 6: ae65.edge1.Stockholm1.Level3.net 35.147ms asymm 7 7: ae-0-11.bar1.SanDiego1.Level3.net 457.605ms asymm 16 8: M5-HOSTING.bar1.SanDiego1.Level3.net 199.025ms asymm 17 9: no reply 10: no reply 11: no reply 12: no reply

usr1106 6y ago

found the answer -M icmp

Sesse__ 6y ago

Forwarding packets happens in ASICs, generating ICMPs is usually done by the CPU (which has a packet rate of maybe 1/100000th of the ASICs). So the latter is usually either rate-limited or turned off entirely, or you could bring the router to its knees by just spamming packets with too short TTL. It's also not uncommon that people turn it off to reduce external insight into their network, for whatever reason.

usr1106 6y ago
Right, but the weird thing was that grand parent got a full trace up to the target and I didn't as usual. By experimenting a bit I found that when sending UDP packets the traceroute is incomplete, but when sending ICMP also my traceroute is complete. Explains how the grandparent could present a full traceroute. I had just taken it as a fact that full traceroutes are rarely possible these days. For reasons like you say, it's overhead for them and they don't want you to do it.