Possible peering/routing issue

[lmineiro]

Yesterday (18th May) I noticed that I wasn't able to reach some hosts and my first suspicion was that the target hosts were to blame since everything else seemed to be working fine. After some more investigation I now think there might be some routing or peering issues.

The hosts from my troubleshooting are: 185.39.10.39 and 85.92.108.102. I've used some command line tools on my mac to diagnose.

1st step: trying to establish a connection:

$ nc -vz 85.92.108.102 8080
nc: connectx to 85.92.108.102 port 8080 (tcp) failed: Operation timed out

$ nc -vz 185.39.10.39 8080
nc: connectx to 185.39.10.39 port 8080 (tcp) failed: Operation timed out

2nd step: establish the path to one of them:

$ traceroute 85.92.108.102
traceroute to 85.92.108.102 (85.92.108.102), 64 hops max, 52 byte packets
 1  fritz.box (192.168.0.1)  3.861 ms  1.068 ms  1.579 ms
 2  ip5b4065fe.dynamic.kabel-deutschland.de (91.64.101.254)  19.031 ms  15.189 ms  16.924 ms
 3  83-169-180-142-isp.superkabel.de (83.169.180.142)  15.727 ms  12.959 ms  16.344 ms
 4  ip53a99c95.static.kabel-deutschland.de (83.169.156.149)  29.252 ms  12.041 ms  10.864 ms
 5  145.254.3.66 (145.254.3.66)  14.303 ms  16.982 ms  9.568 ms
 6  145.254.2.187 (145.254.2.187)  21.009 ms  27.651 ms  26.054 ms
 7  145.254.2.187 (145.254.2.187)  26.374 ms  29.245 ms  35.338 ms
 8  ae4-0.ams10.core-backbone.com (80.249.209.128)  41.625 ms  28.845 ms  64.807 ms
 9  core-backbone.global-layer.com (5.56.20.22)  27.086 ms  51.936 ms  37.298 ms
10  185.23.212.5 (185.23.212.5)  32.319 ms  30.292 ms  31.075 ms
11  185.23.212.9 (185.23.212.9)  91.471 ms  45.881 ms  205.050 ms
12  * * *
13  * * *
14  * * *
15  * * *
16  * * *
17  * *^C

After hop #12 it just goes on and on until it'd hit the 64th hop and give up. This initially suggested that the target host would be down. After checking with 3 friends with the following internet providers/options (1und1, Vodafone-DSL and Vodafone-Kabel such as myself). They all reported being able to establish these connections.

% nc -vz 85.92.108.102 8080
Connection to 85.92.108.102 port 8080 [tcp/http-alt] succeeded!
...
$ nc -vz 85.92.108.102 8080
Connection to 85.92.108.102 8080 port [tcp/http-alt] succeeded!
...
Connection to 85.92.108.102 8080 port [tcp/http-alt] succeeded!

3rd step: Try using a VPN provider (protonvpn):

$ traceroute 85.92.108.102
traceroute to 85.92.108.102 (85.92.108.102), 64 hops max, 52 byte packets
 1  10.1.0.1 (10.1.0.1)  39.161 ms  29.662 ms  57.401 ms
 2  37.120.217.162 (37.120.217.162)  22.439 ms  25.503 ms  31.757 ms
 3  37.120.217.161 (37.120.217.161)  150.143 ms  28.772 ms  37.147 ms
 4  37.120.220.134 (37.120.220.134)  23.753 ms  24.951 ms  31.336 ms
 5  37.120.220.119 (37.120.220.119)  44.062 ms
    37.120.128.148 (37.120.128.148)  29.784 ms  22.751 ms
 6  37.120.128.253 (37.120.128.253)  21.409 ms  25.129 ms  19.930 ms
 7  ae3-1.fra20.core-backbone.com (80.81.192.187)  40.074 ms  26.378 ms  29.766 ms
 8  ae5-2074.ams10.core-backbone.com (81.95.2.138)  41.619 ms  29.200 ms  34.227 ms
 9  core-backbone.global-layer.com (5.56.20.22)  35.442 ms  40.730 ms  54.812 ms
10  185.23.212.5 (185.23.212.5)  37.281 ms  54.610 ms  58.951 ms
11  185.23.212.9 (185.23.212.9)  623.981 ms  96.037 ms  193.490 ms
12  85.92.108.102 (85.92.108.102)  29.099 ms  33.387 ms  30.099 ms

I am able to reach the target host successfully.

I have also forced traceroute to do TCP tracing (traceroute -P TCP -p 8080 85.92.108.102) but that fails as well without the VPN.

Any chances this could be looked into? I feel there's currently a part of the internet I am unable to reach 😞

[Martin59]

Hello lmineiro,

is the disturbance still in progress?

If so, please send me your name, address, date of birth and customer number by PN.   

Please let us know here as soon as you have sent the message.

Best regards, Martin

[lmineiro · Accepted solution]

I've managed to workaround the issue by "forcing" a new DHCP lease for my cable modem. Using the "Reconnect" option in the FritzBox or even turning it off and back on with only a couple of second in between resulted in the same IP addresses being assigned. While I had the same IP addresses (IPv4 and IPv6) the rotuing problem persisted.

After keeping the cable modem off for ~15min and turning it back on I got new DHCP leases - new IPv4 and IPv6 addresses. The problem disappeared immediately and I am now able to reach the targets successfully. What gave me the hint of it being a routing problem was the fact that another Vodafone/Cable customer in Berlin being able to reach the target while I couldn't. The traceroute output for both of us was different (mine never returned).

Let me know if providing you my customer details as well as the old and new IP addresses can help with additional troubleshooting.

Thanks

[Moni_GK]

Hello, Imineiro,

do you notice any interference now, or does it work?

Best regards

Moni

[lmineiro]

It works currrently with my new IP address. I can't guarantee if the problem will come back when my DHCP lease is renewed.

[Moni_GK]

Hello lmineiro,

then keep watching and report back here when the problem is solved.

Best regards

Moni