Logs full of "timed out resolving" entries

[Scott Gasch]

I have a BIND 9.16.3 server running as master for a couple of zones and
forwarding queries to my ISP (and 8.8.8.8 / 8.8.4.4 etc...) for other
queries.  It "works" ok but I notice weird delays in web browsing clients
where the browser says "Resolving host...", hangs for a bit (noticeably, ~a
few seconds), then loads the whole page.

In the server logs, I see lots of messages like this one:

Jun 16 17:21:04 <daemon.info> wannabe named[6982]: timed out resolving '
> trafficmanager.net/DS/IN': 8.8.4.4#53
> Jun 16 17:21:05 <daemon.info> wannabe named[6982]: timed out resolving '
> apiv4-east.myq-cloud.com/AAAA/IN': 8.8.4.4#53


However when I dig from the command line, I can't replicate this.  The
query comes back quickly and successfully:

> # *dig @8.8.4.4 <http://8.8.4.4> apiv4-east.myq-cloud.com
> <http://apiv4-east.myq-cloud.com>*
> ; <<>> DiG 9.16.3 <<>> @8.8.4.4 apiv4-east.myq-cloud.com
> ; (1 server found)
> ;; global options: +cmd
> ;; Got answer:
> ;; ->>HEADER<<- opcode: QUERY, status: NOERROR, id: 52825
> ;; flags: qr rd ra; QUERY: 1, ANSWER: 1, AUTHORITY: 0, ADDITIONAL: 1
> ;; OPT PSEUDOSECTION:
> ; EDNS: version: 0, flags:; udp: 512
> ;; QUESTION SECTION:
> ;apiv4-east.myq-cloud.com.      IN      A
> ;; ANSWER SECTION:
> apiv4-east.myq-cloud.com. 4     IN      A       40.71.236.219
> ;; Query time: *42 msec*
> ;; SERVER: 8.8.4.4#53(8.8.4.4)
> ;; WHEN: Tue Jun 16 17:22:17 PDT 2020
> ;; MSG SIZE  rcvd: 69


It almost feels like something in between me and the next nameserver is
dropping packets when a lot of queries are in flight at the same time.
I've looked at my router logs and it doesn't seem to be the culprit.  When
I run tcpdump, though, I definitely see queries that do not return and are
tried at another DNS server.

Can anyone advise me how to troubleshoot this further, please?

Thx,
Scott
-------------- next part --------------
An HTML attachment was scrubbed...
URL: <https://lists.isc.org/pipermail/bind-users/attachments/20200616/30db31d4/attachment.htm>