(which are similar to DNS Cookies by Donald Eastlake)
and are designed to help clients detect off path
spoofed responses and for servers to detect legitimate
clients.
SIT use a experimental EDNS option code (65001).
SIT can be enabled via --enable-developer or
--enable-sit. It is on by default in Windows.
RRL processing as been updated to know about SIT with
legitimate clients not being rate limited. [RT #35389]