40-85% packet loss to IPv6 Cloudflare DNS in DUS with Vodafone

Hello,

my internet provider is Vodafone (Kabel Deutschland) in germany. AS3209.
Normally I am always redirected to the data center in Düsseldorf in germany.
I have had about 40-85% packet loss to all 6 Cloudflare IPv6 DNS addresses since months.
IPv4 addresses are fine with zero packet loss.

Now I noticed since 1:30 am that I have zero packet loss to all IPv6 but ping times are about 5ms higher now.
I checked https://www.cloudflarestatus.com/ and saw that Düsseldorf, Germany - (DUS) is Re-routed at the moment.

This is my connection information now with the connected data center in Amsterdam.

Traceroutes:
traceroute6 2606:4700:4700::1111
»traceroute« zu 2606:4700:4700::1111 (2606:4700:4700::1111) von 2a02:8108:8580:xxxxx, Port 33434, von Port 60796, maximal 30 Sprünge, 60 Byte Pakete
1 2a02:8108:8580:xxxxx (2a02:8108:8580:xxxxx) 1.109 ms 1.912 ms 1.264 ms
2 2a02:8108:8001:b::1 (2a02:8108:8001:b::1) 13.209 ms 16.085 ms 9.720 ms
3 2a02:8100:6:2::101:701 (2a02:8100:6:2::101:701) 17.204 ms 16.039 ms 9.994 ms
4 2a02:8100:6:2::2:282 (2a02:8100:6:2::2:282) 17.867 ms 15.002 ms *
5 2a00::bfff:0:c02:c02:5 (2a00::bfff:0:c02:c02:5) 16.493 ms 18.107 ms 13.559 ms
6 * * 2a00::140:0:14 (2a00::140:0:14) 24.070 ms
7 ams-ix.as13335.net (2001:7f8:1::a501:3335:1) 37.894 ms 99.476 ms 67.631 ms
8 2400:cb00:20:1024::ac45:3413 (2400:cb00:20:1024::ac45:3413) 30.115 ms 25.924 ms 21.701 ms

traceroute6 2606:4700:4700::1001
»traceroute« zu 2606:4700:4700::1001 (2606:4700:4700::1001) von 2a02:8108:8580:xxxf, Port 33434, von Port 60785, maximal 30 Sprünge, 60 Byte Pakete
1 2a02:8108:8580:xxxxf (2a02:8108:8580:xxxx) 1.390 ms 1.713 ms 1.105 ms
2 2a02:8108:8001:b::1 (2a02:8108:8001:b::1) 11.187 ms 11.499 ms 9.789 ms
3 2a02:8100:6:2::101:701 (2a02:8100:6:2::101:701) 19.602 ms 19.688 ms 11.322 ms
4 * * * …
5 2a00::bfff:0:c02:c02:5 (2a00::bfff:0:c02:c02:5) 16.481 ms 19.889 ms 13.991 ms
6 * * 2a00::140:0:14 (2a00::140:0:14) 23.696 ms
7 ams-ix.as13335.net (2001:7f8:1::a501:3335:1) 35.887 ms 34.704 ms 28.996 ms
8 2400:cb00:20:1024::8d65:40c5 (2400:cb00:20:1024::8d65:40c5) 27.630 ms 30.595 ms 24.024 ms

Kind regards
maik005

Now Düsseldorf is back online and my packet loss is also back with the same 45-80%

Here are the traceroutes now:

traceroute6 2606:4700:4700::1111
»traceroute« zu 2606:4700:4700::1111 (2606:4700:4700::1111) von 2a02:8108:8580:xxxx, Port 33434, von Port 57981, maximal 30 Sprünge, 60 Byte Pakete
1 2a02:8108:8580:xxxxxx (2a02:8108:8580:xxxxxx) 2.469 ms 1.453 ms 2.043 ms
2 2a02:8108:8001:b::1 (2a02:8108:8001:b::1) 10.856 ms 13.142 ms 9.834 ms
3 2a02:8100:6:2::101:701 (2a02:8100:6:2::101:701) 16.924 ms 13.574 ms 10.672 ms
4 * * * …
5 * * * …
6 * * * …
7 * * * …
8 * * * …
9 2400:cb00:48:1024::c629:f119 (2400:cb00:48:1024::c629:f119) 25.124 ms 21.302 ms 18.003 ms

traceroute6 2606:4700:4700::1001
»traceroute« zu 2606:4700:4700::1001 (2606:4700:4700::1001) von 2a02:8108:8580:xxxxx, Port 33434, von Port 57975, maximal 30 Sprünge, 60 Byte Pakete
1 2a02:8108:8580:xxxxx (2a02:8108:8580:xxxx) 2.032 ms 2.096 ms 2.792 ms
2 2a02:8108:8001:b::1 (2a02:8108:8001:b::1) 13.709 ms 7.653 ms 7.389 ms
3 2a02:8100:6:2::101:701 (2a02:8100:6:2::101:701) 12.338 ms 17.619 ms 11.661 ms
4 2a02:8100:6:2::2:282 (2a02:8100:6:2::2:282) 19.400 ms * *
5 2a00::bfff:0:c02:c02:5 (2a00::bfff:0:c02:c02:5) 16.155 ms * *
6 * * * …
7 * * * …
8 2400:cb00:48:1024::c629:f12f (2400:cb00:48:1024::c629:f12f) 25.098 ms 22.624 ms 15.865 ms

Hi, can you add an mtr? It seems like there’s a congestion somewhere on the path, but I’m not sure where because reverse mtr gets filtered as soon as it enters Vodafone’s network:

1	2400:cb00:48:1000::1 	AS13335	10	0.964ms	0.667ms	1.199ms	0.216ms
2	2400:cb00:48:2::c629:f011 	AS13335	10	0.251ms	0.18ms	0.36ms	0.062ms
3	vodafonede-gw.dus.cw.net (2001:5000:0:173::2)	AS1273	4	0.638ms	0.612ms	0.678ms	0.028ms

I am a Vodafone Kabel Deutschland customer too.

VF did apply a fix by cisco to its core routers. IPv6 no longer seem to fail. mtr still looks a bit odd:
image

hello @mvavrusa

thanks for your reply.

As @user6094said Vodafone Germany fixed a problem in their network which solved the paket loss for me.

Also the route from your side should be fine now.

@user6094

The problem you describe with packet loss on the vodafone hops is normal for vodafone as they have a low priority to answer ICMP packets.

As long as you have zero packet loss on the target it is fine.

1 Like

oh, thx. You are the first one saying that. Seems legit, VF’s networks always seem overloaded.

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