> which they should do even when they don't get a response (which they should > report with "no reply", or potentially an error message they got back)
In fact, I can't shake the impression that only those probes that did _not_ get a reply, or got an error message, are the only ones reporting. And those probes that _did_ get a reply don't report it. 12.07.2025 13:54:42 via ripe-atlas <[email protected]>: > I understand the issue is _not_ that packets NTP aren't getting through. > > The issue is that the probes don't report on the results of the measurement > ("no report available"), which they should do even when they don't get a > response (which they should report with "no reply", or potentially an error > message they got back). > > It's not only in the UI, but the data retrievable from the API is also > lacking those reports. > > 12.07.2025 13:43:27 Max Grobecker <[email protected]>: > >> Hi Marco, >> Hi Giovane, >> >> do you know if this only affects ntp0.testdns.nl or could it be a problem >> with NTP packets in general? >> Also, did you do traceroutes/MTRs to the affected probes to see, if there >> are similarities in routing – like the same transit carrier? >> In the past, some carriers (CenturyLink, as an example) had traffic filter >> rules in place on their edges to prevent NTP reflection or amplification >> attacks, that killed regular NTP traffic as well, >> so I assume this could be the case here, too, not necessarily with >> CenturyLink/Colt as the transit. >> >> You could try doing a traceroute with port 123/UDP as the source towards >> these probes to see, if the packets get eaten on some network demarcation: >> >> traceroute -U --sport 123 <ip-of-the-probe> >> >> You will likely not get an answer on the last 1-2 hops (because NAT and >> stateful firewalls), but if there's a carrier in between that discards >> traffic, the traceroute is noticeable shorter. >> >> >> If it helps, you can try with my server ntp2.301-moved.de as well – I have >> access to sflow data from that host, so I can precisely tell if there have >> been answer packets coming from that system. >> >> >> Greetings, >> Max ----- To unsubscribe from this mailing list or change your subscription options, please visit: https://mailman.ripe.net/mailman3/lists/ripe-atlas.ripe.net/ As we have migrated to Mailman 3, you will need to create an account with the email matching your subscription before you can change your settings. More details at: https://www.ripe.net/membership/mail/mailman-3-migration/
