3 ms·
Even if it is required, some authoritative DNS server implementations don't, so far I have found BIND that came with FreeBSD 8.0 doesn't, nor does tinydns. So
by X-Istence 14y ago
Even if it is required, some authoritative DNS server implementations don't, so far I have found BIND that came with FreeBSD 8.0 doesn't, nor does tinydns.
So recursors would have to account for possibly broken implementations and try the query anyway.