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A comment on The journey of an internet packet: Exploring networks with traceroute.

Re:The journey of an internet packet: Exploring networks wit... by jerf on Wednesday August 28, 2024 @10:59AM (#41380280)
I miss traceroute. It seems like more and more, the linked page is hypothetical, and what I get in practice is a couple of hops, an arbitrary number of "* * *" lines, and maybe the last host or two. It's so nice when it works.

    $ traceroute youtube.com
    traceroute to youtube.com (142.250.114.91), 30 hops max, 60 byte packets
     1  10.202.10.88 (10.202.10.88)  0.384 ms  0.356 ms  0.342 ms
     2  10.202.35.103 (10.202.35.103)  36.386 ms  36.370 ms  36.325 ms
     3  10.202.32.4 (10.202.32.4)  36.301 ms 10.202.32.3 (10.202.32.3)  36.301 ms 10.202.32.4 (10.202.32.4)  36.287 ms
     4  10.202.32.2 (10.202.32.2)  0.764 ms  1.279 ms  1.250 ms
     5  lo0-0.gw2.rin1.us.linode.com (45.79.12.102)  0.610 ms lo0-0.gw1.rin1.us.linode.com (45.79.12.101)  0.663 ms  0.650 ms
     6  ae62.r22.dfw01.ien.netarch.akamai.com (23.203.147.40)  0.986 ms  0.881 ms  0.837 ms
     7  72.14.204.254 (72.14.204.254)  1.164 ms 72.14.198.98 (72.14.198.98)  1.153 ms 142.250.47.248 (142.250.47.248)  2.926 ms
     8  * * *
     9  209.85.251.24 (209.85.251.24)  1.082 ms 142.251.71.114 (142.251.71.114)  1.302 ms  0.950 ms
    10  142.251.234.214 (142.251.234.214)  1.267 ms 216.239.58.16 (216.239.58.16)  3.296 ms 142.251.66.192 (142.251.66.192)  20.440 ms
    11  108.170.228.86 (108.170.228.86)  1.161 ms 108.170.228.82 (108.170.228.82)  4.548 ms 108.170.228.81 (108.170.228.81)  1.746 ms
    12  108.170.231.7 (108.170.231.7)  3.484 ms 108.170.229.87 (108.170.229.87)  3.071 ms 142.251.70.211 (142.251.70.211)  2.938 ms
    13  142.250.236.158 (142.250.236.158)  2.298 ms 216.239.51.220 (216.239.51.220)  27.388 ms 108.170.233.60 (108.170.233.60)  2.001 ms
    14  142.250.224.27 (142.250.224.27)  2.085 ms 142.250.224.25 (142.250.224.25)  1.994 ms 142.250.224.23 (142.250.224.23)  2.558 ms
    15  * * *
    16  * * *
    17  * * *
    18  * * *
    19  * * *
    20  * * *
    21  * * *
    22  * * *
    23  * * *
    24  rr-in-f91.1e100.net (142.250.114.91)  1.997 ms  1.981 ms 1.967 ms
Just an example. There's still a lot of stuff that works, but it just seems to me more and more often that when I have an actual problem I'm going to see a lot of * * *. So many things turning the requisite packets off.

(To save people excited to see if I've leaked something important some time, this comes from my Linode-hosted website's box, not my home connection.)

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Re:The journey of an internet packet: Exploring networks wit... by packetslave on Wednesday August 28, 2024 @11:48AM (#41380820)
To be fair, that entire traceroute never touches "the Internet". Everything after hop 6 is inside Google's backbone network, and everything before hop 7 is inside Linode/Akamai.
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Re:The journey of an internet packet: Exploring networks wit... by alexchamberlain on Wednesday August 28, 2024 @02:19PM (#41382515)
So it hits the Internet once between Akamai and Google I guess?
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Re:The journey of an internet packet: Exploring networks wit... by packetslave on Wednesday August 28, 2024 @02:58PM (#41382963)
I mean, KIND OF, if you squint. From the trace, Akamai and Google have a direct peering link (hop 6 looks like an Akamai edge/peering router -- Akamai owns Linode so that makes sense -- and hop 7 is a Google peering router).

For it to be hitting "the Internet" you'd expect to see hops on a Tier 1 carrier like AT&T, Lumen, etc. and/or an ISP like Comcast, Spectrum, etc.

[ Parent | on HN ]
Re:The journey of an internet packet: Exploring networks wit... by Hikikomori on Wednesday August 28, 2024 @05:15PM (#41384461)
It's still the internet, tier 1 carriers aren't special, they're just big.
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Re:The journey of an internet packet: Exploring networks wit... by spelunker on Wednesday August 28, 2024 @11:46AM (#41380790)
traceroute noob - what do the * * * mean? A host is choosing not to participate and dropping data or something?
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Re:The journey of an internet packet: Exploring networks wit... by mccoyc on Wednesday August 28, 2024 @12:10PM (#41381089)
Traceroute works by observing Internet Control Message Protocol (ICMP) time to live/hop count exceeded messages and noting the source IP of those messages. There's plenty of resources you can search on to learn more about this. When you see * * *, it means that for that given TTL value, no corresponding ICMP messages were returned to the source.

It could be because they were filtered at the boundary of the network. If source IPs are private (RFC-1918 or carrier grade NAT space), those ICMP messages should get dropped. This is Best Current Practice (BCP) 38, if you wanted to read more about it.

Ever want to know why IPv6 is so important? This is another reason why. Troubleshooting networks without globally significant IP addresses on the intermediate hops is a real pain.

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Re:The journey of an internet packet: Exploring networks wit... by spelunker on Wednesday August 28, 2024 @12:45PM (#41381429)
Great info, ty!
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