Monitoring problems (again)?

Server operators
1

Since yesterday i am getting “Bad Stratum” errors on some of my servers, (2a02:a46d:7ac:1:f690:eaff:fe00:700e), while they appear to operate perfectly when interrogated from outside the pool ( NTP Server Online Test Tool (IPv4 & IPv6) ).

Can’t figure out if this is my servers having a hiccup or some monitoring fault.

You guys see the same for your servers?

CSV dump:

ts_epoch,ts,offset,step,score,monitor_id,monitor_name,rtt,leap,error
1768334379,2026-01-13 19:59:39,,-4,14.989008904,24,recentmedian,,3,"bad stratum 0 (referenceID: 0x0, <NULL><NULL><NULL><NULL>)"
1768334379,2026-01-13 19:59:39,0.000914876,1,19.801557541,191,frory1-1q8hbq5,11.765,,
1768334331,2026-01-13 19:58:51,,-4,14.989008904,24,recentmedian,,3,"bad stratum 0 (referenceID: 0x0, <NULL><NULL><NULL><NULL>)"
1768334331,2026-01-13 19:58:51,-0.000979786,1,12.045809746,336,nlams1-1x7260p,4.921,,
1768334281,2026-01-13 19:58:01,,-4,14.989008904,24,recentmedian,,3,"bad stratum 0 (referenceID: 0x0, <NULL><NULL><NULL><NULL>)"
1768334281,2026-01-13 19:58:01,0.001152745,1,16.131084442,265,gblhr1-32yzyvc,10.797,,
1768334279,2026-01-13 19:57:59,0.00007725,1,19.966049194,334,frory1-1x7260p,16.678,,
1768334276,2026-01-13 19:57:56,0.000586848,1,17.561624527,299,uarwn2-1bzrttg,30.985,,
1768334228,2026-01-13 19:57:08,,-4,14.989008904,24,recentmedian,,3,"bad stratum 0 (referenceID: 0x0, <NULL><NULL><NULL><NULL>)"
1768334228,2026-01-13 19:57:08,0.000247258,1,17.561624527,177,fihel4-2trgvm8,29.618,,
1768334220,2026-01-13 19:57:00,,-4,14.989008904,24,recentmedian,,3,"bad stratum 0 (referenceID: 0x0, <NULL><NULL><NULL><NULL>)"
1768334220,2026-01-13 19:57:00,0.000404952,1,11.938184738,109,dehhn1-3strqkc,9.287,,
1768334220,2026-01-13 19:57:00,,-4,14.989008904,24,recentmedian,,3,"bad stratum 0 (referenceID: 0x0, <NULL><NULL><NULL><NULL>)"
1768334220,2026-01-13 19:57:00,0.000117469,1,9.164360046,103,nlein1-3strqkc,2.979,,
1768334170,2026-01-13 19:56:10,,-4,14.989008904,24,recentmedian,,3,"bad stratum 0 (referenceID: 0x0, <NULL><NULL><NULL><NULL>)"
1768334170,2026-01-13 19:56:10,0.0032865,1,12.799743652,128,denue1-3strqkc,19.728,,
1768334154,2026-01-13 19:55:54,,-4,14.989008904,24,recentmedian,,3,"bad stratum 0 (referenceID: 0x0, <NULL><NULL><NULL><NULL>)"
1768334154,2026-01-13 19:55:54,0.000463804,1,17.561624527,86,nlams1-1a6a7hp,3.706,,
1768334078,2026-01-13 19:54:38,,-4,14.989008904,24,recentmedian,,3,"bad stratum 0 (referenceID: 0x0, <NULL><NULL><NULL><NULL>)"
1768334078,2026-01-13 19:54:38,0.000142287,1,19.996603012,117,nlams2-1a6a7hp,4.314,,
1768334021,2026-01-13 19:53:41,,-4,14.989008904,24,recentmedian,,3,"bad stratum 0 (referenceID: 0x0, <NULL><NULL><NULL><NULL>)"
1768334021,2026-01-13 19:53:41,0.006848045,1,11.085767746,221,clkna2-k2cg7w,214.389,,
1768334018,2026-01-13 19:53:38,,-4,14.989008904,24,recentmedian,,3,"bad stratum 0 (referenceID: 0x0, <NULL><NULL><NULL><NULL>)"
1768334018,2026-01-13 19:53:38,0.000914463,1,19.7911129,191,frory1-1q8hbq5,11.813,,
1768333968,2026-01-13 19:52:48,,-4,14.989008904,24,recentmedian,,3,"bad stratum 0 (referenceID: 0x0, <NULL><NULL><NULL><NULL>)"
1768333968,2026-01-13 19:52:48,-0.000306726,1,17.561624527,131,searn1-3strqkc,27.046,,
1768333965,2026-01-13 19:52:45,,-4,14.989008904,24,recentmedian,,3,"bad stratum 0 (referenceID: 0x0, <NULL><NULL><NULL><NULL>)"
1768333965,2026-01-13 19:52:45,-0.000807034,1,15.927456856,265,gblhr1-32yzyvc,11.079,,
1768333909,2026-01-13 19:51:49,-0.001730845,1,11.627167702,336,nlams1-1x7260p,4.192,,
1768333858,2026-01-13 19:50:58,,-4,14.989008904,24,recentmedian,,3,"bad stratum 0 (referenceID: 0x0, <NULL><NULL><NULL><NULL>)"
1768333858,2026-01-13 19:50:58,0.000088992,1,8.594062805,103,nlein1-3strqkc,3.19,,
2

Just checked:

root@sprintweb:~# traceroute6 2a02:a46d:7ac:1:f690:eaff:fe00:700e
traceroute to 2a02:a46d:7ac:1:f690:eaff:fe00:700e (2a02:a46d:7ac:1:f690:eaff:fe00:700e), 30 hops max, 80 byte packets
 1  _gateway (2001:1b60:2:1::1)  0.216 ms  0.331 ms  0.369 ms
 2  2001:1b60:0:10:0:1:0:1 (2001:1b60:0:10:0:1:0:1)  0.457 ms  0.426 ms  0.452 ms
 3  2001:1b60:0:12:0:1:0:1 (2001:1b60:0:12:0:1:0:1)  13.506 ms  13.490 ms  13.519 ms
 4  e0-18.core2.ber1.he.net (2001:470:1:a54::1)  21.280 ms  21.560 ms  21.855 ms
 5  * * *

After there are no responses if that helps from Germany.

3

Hmm.

I have seen some strange Bad Stratum problems from Chrony deamon before, but it is weird that this appears to affect mainly one server and not two others using the same chrony instance as well as the same connection:

4

I’d just run “grep chrony /var/log/messages” and concentrate on those findings. This is unlikely to be a pool monitoring problem. Hopefully you have multiple upstream NTP sources configured in case one upstream NTP server acts up.

5

Did you check KPN if they had issues?

As both resolve to kpn. Wouldn’t be the first time they have problems.