new: usr: Add support for EDNS ZONEVERSION option
Dig and named can now make requests with an EDNS ZONEVERSION option present.
Two new named.conf
options have been added, request-zoneversion
and
provide-zoneversion
. request-zoneversion
is off
by default. provide-zoneversion
is on
by default.
Closes #4767
Edited by Mark Andrews