We run three stratum 1 servers and our experience with the V6 monitoring is spotty at best. IPv4 runs fine, no issues. IPv6 on the same servers has repeatedly become unreachable according to the NTP monitoring system over the last several months (each currently sitting at -100). We have validated global reachability using multiple servers located across the globe, looking glasses and RIPE tools, but the NTP monitoring system will still report our V6 as down when all other methods we test with say otherwise. We do not use tunnels for V6, we use multiple peering and transit connections (including HE and Cogent, given their V6 networks are effectively separate as of the time of writing this). I honestly do not know what else we can do.
Monitoring stations timeout to our NTP servers
Following this up, thanks to an above post listing the V4 address of the monitoring system, I was able to lookup the V6 address of the system and then trouble-shoot the return path from our side. It turns out one of our peers appears to be blackholing the return traffic from us to them, so we’ve implemented filtering accordingly and the monitoring system score for our V6 addresses are now increasing. And yes, we’ve opened a ticket with that peer so then can sort out the issue on their end.
For my servers (also in Switzerland) the connection from the production monitoring in Newark is horrible over IPv4. Over IPv6, it is just perfect:
Is there something somebody can do to ameliorate the situation?
Same here,
Server with IPv4 & IPv6.
IPv6 score drops below 14 and IPv5 score is stabe at 20.
@ask, where are you with it now?
Is the code accessible that one can submit possible fixes?
I tried to add my servers to this monitoring development, but it does not seem to work.
I am also having the same issue.
On the product ntppool:
https://www.pool.ntp.org/scores/45.76.111.149
https://www.pool.ntp.org/scores/2401:c080:1000:4175:5400:2ff:fe32:f445
Server is based in Japan.
IPv6 is solid ; IPv4 keeps oscillating
I was almost pulling my hair out - since all my tests from multiple servers and locations (US, IN, Japan) were 100% positive.
Now I loaded these to the beta pool.
https://web.beta.grundclock.com/scores/45.76.111.149
https://web.beta.grundclock.com/scores/2401:c080:1000:4175:5400:2ff:fe32:f445
These were just put today - so they haven’t yet reached the perfect 20. However the trend is very clearly visible - especially for the IPv4 interface. Newark keeps reporting a timeout - not sure if it is behaving any better than the production pool ?
Any ideas how to improve the situation - due to this issue, I guess the pool effective capacity is much lesser than what it should be? If the transport related issues are not easily solvable; is it an option to tweak the score downgrade that the Newark monitor gives - so that it is not downgraded so aggressively? What is also puzzling is why the transport is OK for some polls, and not the others ?
i have the same problem here in italy but only from isp fastweb and tiscali
ipv4 score floating 10/14
ipv6 score 20
from isp wind i have
ipv4 score 20
ipv6 score 20
1565817537,"2019-08-14 21:18:57",0.00379887,1,7.3,,,0,
1565816626,"2019-08-14 21:03:46",0,-5,6.6,6,"Newark, NJ, US",,"i/o timeout"
1565816626,"2019-08-14 21:03:46",0,-5,6.6,,,,"i/o timeout"
1565815642,"2019-08-14 20:47:22",0.001398844,1,12.3,6,"Newark, NJ, US",0,
1565815642,"2019-08-14 20:47:22",0.001398844,1,12.3,,,0,
1565814669,"2019-08-14 20:31:09",0.001399639,1,11.9,6,"Newark, NJ, US",0,
1565814669,"2019-08-14 20:31:09",0.001399639,1,11.9,,,0,
1565813742,"2019-08-14 20:15:42",0.002030171,1,11.4,6,"Newark, NJ, US",0,
1565813742,"2019-08-14 20:15:42",0.002030171,1,11.4,,,0,
1565812824,"2019-08-14 20:00:24",0.002168236,1,11,6,"Newark, NJ, US",0,
1565812824,"2019-08-14 20:00:24",0.002168236,1,11,,,0,
1565811916,"2019-08-14 19:45:16",0.002224739,1,10.5,6,"Newark, NJ, US",0,
1565811916,"2019-08-14 19:45:16",0.002224739,1,10.5,,,0,
1565810982,"2019-08-14 19:29:42",0.001927572,1,10,6,"Newark, NJ, US",0,
1565810982,"2019-08-14 19:29:42",0.001927572,1,10,,,0,
1565809981,"2019-08-14 19:13:01",0.002043029,1,9.5,6,"Newark, NJ, US",0,
1565809981,"2019-08-14 19:13:01",0.002043029,1,9.5,,,0,
1565808980,"2019-08-14 18:56:20",0.001458194,1,8.9,6,"Newark, NJ, US",0,
1565808980,"2019-08-14 18:56:20",0.001458194,1,8.9,,,0,
1565808019,"2019-08-14 18:40:19",0.001889322,1,8.3,6,"Newark, NJ, US",0,
1565808019,"2019-08-14 18:40:19",0.001889322,1,8.3,,,0,
1565807110,"2019-08-14 18:25:10",0,-5,7.7,6,"Newark, NJ, US",,"i/o timeout"
1565807110,"2019-08-14 18:25:10",0,-5,7.7,,,,"i/o timeout"The beta site also has a monitor in Amsterdam; I’m curious if (anecdotally) the Amsterdam one is getting different/better results. (Also, the beta site has a bazillion other changes around adding and managing the servers that could use some testing!)
When I click on that link, it gives me a:
500 - Server Error
Ouch! That didn’t work, our server hit a bad gear.
I am logged into the beta site…
Me too. I’m sure it was working yesterday 
Hi,
I’m happy to report that the IPv4 score of the server is now much much better and as solid as the IPv6 side.
Last reported timeout from the Newark monitoring server was at the below time, and the last successful monitoring request was 2019-08-18 07:05:41; so ~5 days and score is now a solid 20.
1565687391,“2019-08-13 09:09:51”,0,-5,-2.8,6,“Newark, NJ, US”,“i/o timeout”
I have not changed anything impacting this on my end - so something else has changed for the good and hopefully it stays that way 
!
Thanks!
Hi,
since yesterday 21:00 MESZ I get on all of my servers
1566222048,“2019-08-19 13:40:48”,0,-5,-8.7,6,“Newark, NJ, US”,“i/o timeout”
CU
Jörg
Hi Jörg, tracerouting to and from the monitoring servers may help you work out where the routing’s broken. This page https://dev.ntppool.org/monitoring/network-debugging/ gives the monitoring server IPs and a tool to traceroute back to your servers (replace the 8.8.8.8 with your IP).
Hi,
here are a traceroute:
curl http://trace.ntppool.org/traceroute/85.93.91.145
Traceroute to 85.93.91.145
1 (139.178.64.41) AS54825 20.300 20.262
2 (147.75.98.106) AS54825 11.808
2 0.xe-0-0-17.dsr1.ewr1.packet.net (147.75.98.104) AS54825 8.295
3 0.ae12.bbr1.ewr1.packet.net (198.16.4.88) AS54825 1.812 1.794
4 39.ae39.bbr1.jfk3.packet.net (192.80.8.99) AS54825 1.273 1.265
5 (64.125.54.25) AS6461 1.961
5 39.ae39.bbr1.jfk3.packet.net (192.80.8.99) AS6461 1.218
6 (64.125.54.25) AS6461 2.165 *
7 * *
8 ae27.mpr2.lhr2.uk.zip.zayo.com (64.125.30.237) AS6461 67.003 *
9 ae27.mpr2.lhr2.uk.zip.zayo.com (64.125.30.237) AS6461 67.160 67.414
10 (195.66.225.173) 71.336
10 ae11.mpr1.lhr15.uk.zip.zayo.com (64.125.30.53) AS6461 66.790
11 (195.66.225.173) 71.373
11 ae0.cr-merak.lon5.bb.godaddy.com (87.230.113.1) AS20773 72.024
12 ae0.cr-merak.lon5.bb.godaddy.com (87.230.113.1) AS20773 72.182 72.135
13 (87.230.112.3) AS20773 81.000
13 ae0.cr-nunki.sxb1.bb.godaddy.com (87.230.113.3) AS20773 81.189
14 (87.230.112.3) AS20773 81.965
14 (62.138.129.10) AS20773 84.873
15 (62.138.129.10) AS20773 85.118 83.234
16 snct3.snct-dialer.de (85.93.91.145) AS8972 80.914 80.874
With ping I get a 404:
curl http://trace.ntppool.org/ping/85.93.91.145
404 page not found
Hi,
I’m trying debug problems with monitoring of my server. When I try trace.ntppool.org/traceroute using curl it seems not working correctly:
curl https://trace.ntppool.org/traceroute/62.197.224.14
Traceroute to 62.197.224.14
1 (139.178.64.41) AS54825 19.720 19.683
2 0.xe-0-0-17.dsr2.ewr1.packet.net (147.75.98.106) AS54825 17.796 17.776
3 (198.16.4.86) AS54825 0.540
3 0.ae11.bbr1.ewr1.packet.net (198.16.4.84) AS54825 0.444
iwik@[avenger]:~$ curl https://trace.ntppool.org/traceroute/62.197.224.14
Traceroute to 62.197.224.14
1 (139.178.64.41) AS54825 11.906 11.869
2 (147.75.98.104) AS54825 15.445
2 0.xe-0-0-17.dsr2.ewr1.packet.net (147.75.98.106) AS54825 12.283
3 (198.16.4.88) AS54825 0.516
3 0.ae22.bbr2.ewr1.packet.net (198.16.4.90) AS54825 0.464
iwik@[avenger]:~$ curl https://trace.ntppool.org/traceroute/62.197.224.14
Traceroute to 62.197.224.14
1 (139.178.64.41) AS54825 14.637 14.591
2 (147.75.98.106) AS54825 29.749
2 0.xe-0-0-17.dsr1.ewr1.packet.net (147.75.98.104) AS54825 13.531
iwik@[avenger]:~$ curl https://trace.ntppool.org/traceroute/62.197.224.14
Traceroute to 62.197.224.14
1 (139.178.64.41) AS54825 21.024 20.988
2 (147.75.98.104) AS54825 20.128
2 0.xe-0-0-17.dsr2.ewr1.packet.net (147.75.98.106) AS54825 20.041
3 0.ae12.bbr1.ewr1.packet.net (198.16.4.88) AS54825 0.421 0.413
iwik@[avenger]:~$ curl https://trace.ntppool.org/traceroute/62.197.224.14
Traceroute to 62.197.224.14
1 (139.178.64.41) AS54825 11.749 11.705
2 0.xe-0-0-17.dsr1.ewr1.packet.net (147.75.98.104) AS54825 12.831 12.809
From web browser output is better
Traceroute to 62.197.224.14
1 (139.178.64.41) AS54825 42.988 42.949
2 0.xe-0-0-17.dsr1.ewr1.packet.net (147.75.98.104) AS54825 21.007 20.992
3 0.ae12.bbr1.ewr1.packet.net (198.16.4.88) AS54825 0.453 0.446
4 (198.16.4.81) AS54825 0.269
4 39.ae39.bbr1.jfk3.packet.net (192.80.8.99) AS54825 1.090
5 (64.125.54.25) AS6461 1.187
5 39.ae39.bbr1.jfk3.packet.net (192.80.8.99) AS6461 1.280
6 64.125.54.25.available.above.net (64.125.54.25) AS6461 * 1.121
7 * *
8 (64.125.29.127) AS6461 79.624
8 ae0.cs1.lhr15.uk.eth.zayo.com (64.125.29.119) AS6461 79.210
9 (64.125.29.16) AS6461 79.328
9 ae0.cs1.lhr15.uk.eth.zayo.com (64.125.29.119) AS6461 79.201
10 (64.125.29.16) AS6461 79.188
10 ae0.cs1.ams17.nl.eth.zayo.com (64.125.29.81) AS6461 80.876
11 (64.125.29.58) AS6461 79.368
11 ae0.cs1.ams17.nl.eth.zayo.com (64.125.29.81) AS6461 80.699
12 ae0.cs1.fra9.de.eth.zayo.com (64.125.29.55) AS6461 79.216 79.319
13 (64.125.29.55) AS6461 79.301
13 ae27.mpr1.fra4.de.zip.zayo.com (64.125.30.255) AS6461 81.376
14 gwup.dc.ba.gts.sk (80.81.193.195) 96.288 97.063
15 (62.168.99.66) AS5578 98.704
15 gwup.dc.ba.gts.sk (80.81.193.195) AS5578 97.166
16 (195.168.61.115) AS5578 96.726
16 se-0-1-0-0.gwa.husarik.ca.gts.sk (62.168.99.66) AS5578 98.820
17 (62.197.224.14) AS16160 100.444
17 b3.ibm.ke.cust.gts.sk (195.168.61.115) AS16160 96.700
18 * *
19 * *
Next try:
Traceroute to 62.197.224.14
1 (139.178.64.41) AS54825 10.950 10.902
2 0.xe-0-0-17.dsr1.ewr1.packet.net (147.75.98.104) AS54825 12.076 12.060
3 0.ae22.bbr2.ewr1.packet.net (198.16.4.90) AS54825 1.154 0.886
4 (198.16.4.81) AS54825 0.486
4 39.ae39.bbr1.jfk3.packet.net (192.80.8.99) AS54825 1.121
5 (192.80.8.99) AS54825 1.107
5 64.125.54.25.available.above.net (64.125.54.25) AS54825 1.149
6 64.125.54.25.available.above.net (64.125.54.25) AS6461 1.129 1.341
7 * *
8 ae0.cs1.lhr15.uk.eth.zayo.com (64.125.29.119) AS6461 79.803 *
9 ae0.cs1.lhr15.uk.eth.zayo.com (64.125.29.119) AS6461 77.266 77.432
10 (64.125.29.16) AS6461 77.468
10 ae0.cs1.ams17.nl.eth.zayo.com (64.125.29.81) AS6461 77.393
11 ae0.cs1.ams17.nl.eth.zayo.com (64.125.29.81) AS6461 77.359 77.547
12 (64.125.29.55) AS6461 101.687
12 ae2.cs1.fra6.de.eth.zayo.com (64.125.29.58) AS6461 77.459
13 (64.125.30.255) AS6461 77.253
13 ae0.cs1.fra9.de.eth.zayo.com (64.125.29.55) AS6461 92.128
14 gwup.dc.ba.gts.sk (80.81.193.195) 90.545 90.271
15 (62.168.99.66) AS5578 90.374
15 gwup.dc.ba.gts.sk (80.81.193.195) AS5578 90.226
16 (62.168.99.66) AS5578 90.242
16 b3.ibm.ke.cust.gts.sk (195.168.61.115) AS5578 89.786
17 (195.168.61.115) AS5578 89.767
17 cloud.zazezi.net (62.197.224.14) AS5578 94.957
18 cloud.zazezi.net (62.197.224.14) AS16160 93.752 93.786
According to this, routing at first attempt is some strange at the end?
Hi @jff, your server is currently showing a steady score over 10 and seems to be missing only a few monitoring pings so it’s in the pool at the moment. The problem with internet routing is that it changes so unless you happen to catch it while it’s not responding it’s impossible to work out where the issue is… 
@iwik, I’m seeing similar drops at packet.net - maybe it’s worth an email to them (or your ISP) to see if they can investigate.
I’m seeing the same, much less reliable monitoring from NJ. (Still reachable fine in my own testing from various locations around the internet.)
The same problem here. I have an NTP server with IPv6 interface. Since the last two days ( https://www.ntppool.org/scores/2a00:6d40:60:80a0::1 ) my server started getting reachability errors from Newark, NJ monitoring station. I think there is a problem with that monitoring station. The NTP Status page ( https://status.ntppool.org/ ) shows a dramatic drop in IPv6 servers. The problem may be only on the IPv6 network side of the monitoring station.
Yes, I should have specified IPv6. https://www.ntppool.org/zone/north-america says 40% of NA IPv6 servers disappeared since yesterday…
Hi, one of the volunteer admins here. We’re seeing issues with IPv6 monitoring at the moment - I have flagged them to @ask to take a look when he’s next online.
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