[GTALUG] DNS oddities
D. Hugh Redelmeier
hugh at mimosa.com
Thu Sep 15 14:55:24 EDT 2022
[This probably has nothing to do with gtalg.og problems.]
I run a recursive DNS server on my Rogers cable internet connection.
I has stopped working today. (It did this once on the weekend but healed
after a few hours.)
Symptom: nothing resolves. But I'm still able to use the internet via
cached name server info.
Refined symptom:
$ dig gtalug.org + trace
yields nothing but a timeout. Not even intermediat results.
Hypothesis: Rogers is blocking accesss to the root name servers.
Test:
$ mtr i.root-servers.net. # this is a root name server
================================================================
My traceroute [v0.85]
reddoor.mimosa.com (::) Thu Sep 15 14:32:38 2022
Keys: Help Display mode Restart statistics Order of fields quit
Packets Pings
Host Loss% Snt Last Avg Best Wrst StDev
1. 2607:f798:804:f4::1 0.0% 27 7012. 273.2 11.0 7012. 1346.
2. 2607:f798:10:4cf:0:241:5614:2189 0.0% 27 23.2 14.7 10.7 29.0 3.8
3. 2607:f798:10:4a5:0:2091:4823:2082 0.0% 27 13.3 14.1 10.7 22.7 2.7
4. 2607:f798:10:ea48:0:721:3913:6098 0.0% 27 15.6 13.9 10.5 20.7 2.1
5. 2607:f798:10:378:0:2091:4823:7021 0.0% 27 21.9 25.8 20.1 39.5 4.7
6. be812.ccr41.ord03.atlas.cogentco.com 80.8% 27 20.8 23.3 20.8 25.7 1.7
7. be2765.ccr41.ord01.atlas.cogentco.com 80.8% 27 36.4 28.4 21.7 36.4 5.3
8. be3180.rcr21.ind01.atlas.cogentco.com 19.2% 27 30.5 30.2 26.9 35.7 1.9
9. be3365.ccr42.atl01.atlas.cogentco.com 74.1% 27 38.9 45.1 38.9 52.9 5.5
10. be3483.ccr22.mia01.atlas.cogentco.com 80.8% 27 54.7 54.7 53.2 55.9 0.9
11. be3087.ccr41.mia03.atlas.cogentco.com 96.2% 27 55.1 55.1 55.1 55.1 0.0
12. 2001:550:2:4a::90:2 0.0% 27 116.4 116.8 113.7 122.9 2.0
13. 2800:68:ffff:1:: 0.0% 27 126.3 128.3 125.4 135.6 1.9
14. 2800:68:ffff:1::1 0.0% 26 127.3 128.2 124.7 137.0 2.1
15. i.root-servers.net 0.0% 25 7080. 406.6 125.8 7080. 1390.
================================================================
Notice all the lost packets on cogentoco nodes.
Here's the same mtr command, this time run on my Vybe Networks VDSL line:
================================================================
redhop-mimosa-com (98.158.128.23) -> i.root-servers.net. (192.36.148.17) 2022-09-15T14:34:24-0400
Keys: Help Display mode Restart statistics Order of fields quit
Packets Pings
Host Loss% Snt Last Avg Best Wrst StDev
1. _gateway 0.0% 82 17.2 17.6 16.8 25.1 0.9
2. 216.105.84.14 0.0% 82 17.7 17.6 17.0 18.2 0.3
3. 10.77.77.2 0.0% 82 17.5 17.4 16.9 18.2 0.3
4. te0-1-1-4.ccr32.yyz02.atlas.cogentco.com 0.0% 81 19.1 19.1 18.5 20.2 0.3
5. be2994.ccr22.cle04.atlas.cogentco.com 0.0% 81 25.2 25.7 25.1 26.4 0.3
6. be2718.ccr42.ord01.atlas.cogentco.com 0.0% 81 32.2 34.8 31.6 123.7 12.7
7. be2832.ccr22.mci01.atlas.cogentco.com 0.0% 81 43.7 44.2 43.4 65.5 2.4
8. be3036.ccr22.den01.atlas.cogentco.com 0.0% 81 55.2 55.2 54.6 55.9 0.3
9. be3038.ccr32.slc01.atlas.cogentco.com 0.0% 81 65.4 65.6 65.0 66.6 0.3
10. be2029.ccr22.sea02.atlas.cogentco.com 0.0% 81 85.7 85.6 85.0 89.3 0.5
11. be3705.rcr51.b042840-1.sea02.atlas.cogentco.com 0.0% 81 85.5 85.6 85.0 86.3 0.3
12. 38.88.252.178 0.0% 81 85.1 85.8 84.9 122.9 4.2
13. tky001bb00.IIJ.Net 0.0% 81 166.9 168.7 166.6 213.0 5.6
14. tky001ix11.IIJ.Net 0.0% 81 173.2 173.6 172.3 207.4 3.9
15. as8674.dix-ie.jp 0.0% 81 172.6 176.5 172.2 276.9 15.7
16. i.root-servers.net 1.2% 81 167.3 169.5 166.6 226.5 9.3
================================================================
This has no lost packets.
Is this relevant?
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