RING measurements don't match access-networks (Was: Some very nice broken IPv6 networks...)

Jeroen Massar jeroen at massar.ch
Tue Nov 11 12:56:06 CET 2014


On 2014-11-11 06:38, Matthew Luckie wrote:
>> Also, broken pMTU/traceroute for:
>>
>> 2a02:58:3:110::23:1
>> 2a01:310:8312:1001::19
>> 2a00:1f00:dc06:11::10
>> 2001:48c8:3:2::2
>> 2607:fcc0:2:1:208:70:247:50
>> 2001:67c:2274:4021::101
> 
> I took a look at the tracepath information you sent for these nodes,
> which showed a bunch of unresponsive nodes but no information that
> might be useful for assigning blame.  It'd be cool to see these paths
> with scamper's pmtud traceroute, which tries to find out the MTU for
> the hops that aren't sending a PTB.
> 
> with that list of IP addresses:
> scamper -c "trace -P udp-paris -M" -f <file>

See attached f.out, though I used:

(for i in `cat f`; do echo "==================== $i"; tracepath6 -n $i;
scamper -I "trace -P udp-paris -M $i"; done) >>f.out

This to show the difference between tracepath6 and scamper output, there
are some to be seen, some quite scary (eg the 1455 change).
Could be that one just gets through the ICMP ratelimits in one run and
not the other.

Those nodes are just blackholes it seems. Only the operators of that
network will know what is going on.

I am always surprised to see networks filtering out packets, and
especially wonder what they are trying to achieve with such a filter.

> http://www.caida.org/tools/measurement/scamper/
> http://www.caida.org/~mjl/pubs/debugging-pmtud.imc2005.pdf
> 
> Happy to help anyway I can (I wrote scamper)

I am quite aware. Great tool, but not very verbose unfortunately. Hence,
typically it just does/outputs nothing.

Greets,
 Jeroen

-------------- next part --------------
==================== 2a02:58:3:110::23:1
 1?: [LOCALHOST]                        0.032ms pmtu 1500
 1:  2a02:2528:fa:420::1                                   0.192ms 
 1:  2a02:2528:fa:420::1                                   0.132ms 
 2:  2a02:2528:503:2::ffff                                 1.538ms 
 3:  2a02:2528:502:1::1                                    2.202ms 
 4:  2a02:2528:2:10::1                                     5.292ms 
 5:  2a02:2528:102:11::2                                   5.444ms 
 6:  2001:7f8:1::a502:5596:2                              17.855ms asymm 11 
 7:  2a02:58:1:7::2                                       17.954ms asymm 12 
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     Too many hops: pmtu 1500
     Resume: pmtu 1500 
traceroute from 2a02:2528:fa:420::66 to 2a02:58:3:110::23:1
 1  2a02:2528:fa:420::1  0.182 ms
 2  2a02:2528:503:2::ffff  0.938 ms
 3  2a02:2528:502:1::1  1.786 ms
 4  2a02:2528:2:10::1  4.944 ms
 5  2a02:2528:102:11::2  5.079 ms
 6  2001:7f8:1::a502:5596:2  16.995 ms
 7  2a02:58:1:7::2  44.857 ms
 8  *
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12  *
==================== 2a01:310:8312:1001::19
 1?: [LOCALHOST]                        0.039ms pmtu 1500
 1:  2a02:2528:fa:420::1                                   0.194ms 
 1:  2a02:2528:fa:420::1                                   0.091ms 
 2:  2a02:2528:503:2::ffff                                 1.634ms 
 3:  2a02:2528:502:1::1                                    2.311ms 
 4:  2001:7f8:c:8235:194:42:48:80                          2.443ms 
 5:  2001:7f8:24::ad                                       2.820ms 
 6:  2a02:d28:5580:1::a2                                  20.273ms asymm  8 
 7:  2a02:d28:5580::1:36                                  21.341ms asymm  8 
 8:  2a02:d28:5580:1::145                                 18.296ms asymm  9 
 9:  2a02:d28:5580:1::21                                  18.587ms asymm 10 
10:  2a02:d28:5580:e:1000::136                            20.784ms asymm 12 
11:  2a01:310:8312:3900::2                                18.910ms asymm 12 
12:  2a01:310:8312:3900::2                               116.437ms !H
     Resume: pmtu 1500 
traceroute from 2a02:2528:fa:420::66 to 2a01:310:8312:1001::19
 1  2a02:2528:fa:420::1  0.178 ms [mtu: 1500]
 2  2a02:2528:503:2::ffff  0.903 ms [mtu: 1500]
 3  2a02:2528:502:1::1  1.766 ms [mtu: 1500]
 4  2001:7f8:c:8235:194:42:48:80  4.587 ms [mtu: 1500]
 5  2001:7f8:24::ad  34.885 ms [mtu: 1500]
 6  2a02:d28:5580:1::a2  17.056 ms [mtu: 1500]
 7  2a02:d28:5580::1:36  17.007 ms [mtu: 1500]
 8  2a02:d28:5580:1::145  17.549 ms [mtu: 1500]
 9  2a02:d28:5580:1::21  17.820 ms [mtu: 1500]
10  2a02:d28:5580:e:1000::136  22.252 ms [mtu: 1500]
11  2a01:310:8312:3900::2  18.061 ms [*mtu: 1455]
12  *
13  *
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15  2a01:310:8312:3900::2  367.002 ms !A [*mtu: 1455]
==================== 2a00:1f00:dc06:11::10
 1?: [LOCALHOST]                        0.036ms pmtu 1500
 1:  2a02:2528:fa:420::1                                   0.156ms 
 1:  2a02:2528:fa:420::1                                   0.098ms 
 2:  2a02:2528:503:2::ffff                                 1.793ms 
 3:  2a02:2528:502:1::1                                    2.408ms 
 4:  2a02:2528:2:10::1                                     5.512ms 
 5:  2a02:2528:102:11::2                                   5.695ms 
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     Too many hops: pmtu 1500
     Resume: pmtu 1500 
traceroute from 2a02:2528:fa:420::66 to 2a00:1f00:dc06:11::10
 1  2a02:2528:fa:420::1  0.186 ms
 2  2a02:2528:503:2::ffff  1.232 ms
 3  2a02:2528:502:1::1  1.836 ms
 4  2a02:2528:2:10::1  4.918 ms
 5  2a02:2528:102:11::2  5.104 ms
 6  *
 7  *
 8  *
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10  *
==================== 2001:48c8:3:2::2
 1?: [LOCALHOST]                        0.036ms pmtu 1500
 1:  2a02:2528:fa:420::1                                   0.154ms 
 1:  2a02:2528:fa:420::1                                   0.114ms 
 2:  2a02:2528:503:2::ffff                                 1.646ms 
 3:  2a02:2528:502:1::1                                    2.389ms 
 4:  2a02:2528:2:10::1                                     5.454ms 
 5:  2a02:2528:102:11::2                                   5.665ms 
 6:  2001:7f8:1::a502:9791:1                              24.416ms asymm  8 
 7:  2001:48c8::8fd                                       31.732ms 
 8:  2001:48c8::8f9                                       24.693ms 
 9:  2001:48c8::8f6                                       98.524ms asymm 10 
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     Too many hops: pmtu 1500
     Resume: pmtu 1500 
traceroute from 2a02:2528:fa:420::66 to 2001:48c8:3:2::2
 1  2a02:2528:fa:420::1  0.184 ms
 2  2a02:2528:503:2::ffff  0.834 ms
 3  2a02:2528:502:1::1  1.847 ms
 4  2a02:2528:2:10::1  5.042 ms
 5  2a02:2528:102:11::2  5.139 ms
 6  2001:7f8:1::a502:9791:1  32.930 ms
 7  2001:48c8::8fd  27.680 ms
 8  2001:48c8::8f9  24.083 ms
 9  2001:48c8::8f6  97.790 ms
10  *
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==================== 2607:fcc0:2:1:208:70:247:50
 1?: [LOCALHOST]                        0.043ms pmtu 1500
 1:  2a02:2528:fa:420::1                                   0.181ms 
 1:  2a02:2528:fa:420::1                                   0.099ms 
 2:  2a02:2528:503:2::ffff                                 1.732ms 
 3:  2a02:2528:502:1::1                                    2.242ms 
 4:  2a02:2528:2:10::1                                     5.488ms 
 5:  2a02:2528:102:11::2                                   5.552ms 
 6:  2001:7f8:1::a500:6327:1                              28.500ms 
 7:  2001:4e8:0:80e3::1                                   28.967ms 
 8:  2001:4e8:0:80e1::1                                  117.575ms 
 9:  2001:4e8:0:8078::2                                  127.384ms 
10:  2001:4e8:0:807b::2                                  125.705ms 
11:  2001:4e8:0:8118::2                                  148.095ms 
12:  2001:4e8:0:81ea::2                                  148.563ms 
13:  2001:4e8:0:82e9::1                                  192.749ms 
14:  2001:4e8:0:821d::1                                  195.749ms 
15:  2001:4e8:0:8244::2                                  199.906ms 
16:  2607:ffb0:0:8032::2                                 199.666ms 
17:  2607:ffb0:0:4008::2                                 201.534ms 
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     Too many hops: pmtu 1500
     Resume: pmtu 1500 
traceroute from 2a02:2528:fa:420::66 to 2607:fcc0:2:1:208:70:247:50
 1  2a02:2528:fa:420::1  0.211 ms
 2  2a02:2528:503:2::ffff  0.806 ms
 3  2a02:2528:502:1::1  1.856 ms
 4  2a02:2528:2:10::1  4.956 ms
 5  2a02:2528:102:11::2  4.898 ms
 6  2001:7f8:1::a500:6327:1  26.782 ms
 7  2001:4e8:0:80e3::1  28.820 ms
 8  2001:4e8:0:80e1::1  112.821 ms
 9  2001:4e8:0:8078::2  126.841 ms
10  2001:4e8:0:807b::2  125.540 ms
11  2001:4e8:0:8118::2  146.798 ms
12  2001:4e8:0:8109::2  179.185 ms
13  2001:4e8:0:82f5::1  193.214 ms
14  2001:4e8:0:8196::1  187.590 ms
15  2001:4e8:0:822b::2  207.010 ms
16  2607:ffb0:0:8032::2  198.795 ms
17  2607:ffb0:0:4008::2  204.962 ms
18  *
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==================== 2001:67c:2274:4021::101
 1?: [LOCALHOST]                        0.041ms pmtu 1500
 1:  2a02:2528:fa:420::1                                   0.145ms 
 1:  2a02:2528:fa:420::1                                   0.124ms 
 2:  2a02:2528:503:2::ffff                                 1.745ms 
 3:  2a02:2528:502:1::1                                    2.251ms 
 4:  2a02:2528:2:10::1                                     5.490ms 
 5:  2a02:2528:102:11::2                                   5.683ms 
 6:  2001:7f8:1::a501:3237:1                              20.869ms 
 7:  2001:7f0:0:29::1                                     16.973ms asymm  6 
 8:  2001:7f0:0:2b::2                                     17.296ms asymm  5 
 9:  2001:7f0:0:d::2                                      23.504ms asymm  7 
10:  2001:7f0:1:1::2                                      23.544ms asymm  6 
11:  2001:a60::89:705                                     26.466ms asymm  6 
12:  2001:a60:0:227::2                                    33.647ms asymm  7 
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     Too many hops: pmtu 1500
     Resume: pmtu 1500 
traceroute from 2a02:2528:fa:420::66 to 2001:67c:2274:4021::101
 1  2a02:2528:fa:420::1  0.201 ms
 2  2a02:2528:503:2::ffff  0.836 ms
 3  2a02:2528:502:1::1  1.884 ms
 4  2a02:2528:2:10::1  4.961 ms
 5  2a02:2528:102:11::2  4.835 ms
 6  2001:7f8:1::a501:3237:1  27.426 ms
 7  2001:7f0:0:29::1  16.463 ms
 8  2001:7f0:0:2b::2  16.503 ms
 9  2001:7f0:0:d::2  22.581 ms
10  2001:7f0:1:1::2  22.933 ms
11  2001:a60::89:705  23.393 ms
12  2001:a60:0:227::2  28.103 ms
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