I fixed the problem with bind option minimal-responses yes; there was saturation of dns server's accept queue (bind has value of 10 by default). nothing has to do with blackbox in general I guess. Ty Ben Kochie for the insight on dns response size.
On Fri, Aug 26, 2022 at 12:15 AM Brian Candler <[email protected]> wrote: > On Thursday, 25 August 2022 at 11:36:59 UTC+1 [email protected] wrote: > >> 1) [image: 2022-08-25_20-10-14.png] >> >> 2) I was checking with tcpdump. Don't know if I'm on pair with your >> theory cause client (blackbox) sending syn immediately after receiving >> "large" udp packet. >> > > Does tcpdump decode this "large" udp response? Is it a valid DNS packet? > > If the resolver switches to TCP immediately - which it is entitled to - > this then begs the question of where the 3 second delay is coming from. > Again, more tcpdump analysis may be required. > > -- > You received this message because you are subscribed to a topic in the > Google Groups "Prometheus Users" group. > To unsubscribe from this topic, visit > https://groups.google.com/d/topic/prometheus-users/02s1zRIBTTY/unsubscribe > . > To unsubscribe from this group and all its topics, send an email to > [email protected]. > To view this discussion on the web visit > https://groups.google.com/d/msgid/prometheus-users/14e86df9-e50d-4142-9947-2a56244d00aen%40googlegroups.com > <https://groups.google.com/d/msgid/prometheus-users/14e86df9-e50d-4142-9947-2a56244d00aen%40googlegroups.com?utm_medium=email&utm_source=footer> > . > -- You received this message because you are subscribed to the Google Groups "Prometheus Users" group. To unsubscribe from this group and stop receiving emails from it, send an email to [email protected]. To view this discussion on the web visit https://groups.google.com/d/msgid/prometheus-users/CAD4d9sw1A%3D-Yym%2B%2B-64e1UjhNEapG0u-1ErMD7ck5JE1Vu%2BqeQ%40mail.gmail.com.
