TCP connections left in CLOSE_WAIT
Summary
From https://lists.isc.org/pipermail/bind-users/2021-May/104682.html and https://lists.isc.org/pipermail/bind-users/2021-June/104698.html .
After updating public authoritative servers from 9.16.6/9.16.8 to 9.16.15/9.16.16 there is an issue with TCP connections building up in CLOSE_WAIT status until named is restarted.
These appear to be client resolver queries for large TXT records where the client is not EDNS capable.
Requires keep-response-order { any; }
(not default) to be configured to disable TCP-pipelining.