ar@cello ~ % ping -4c1 a.root-servers.net.; ping -6c1 a.root-servers.net.
PING a.root-servers.net (198.41.0.4) 56(84) bytes of data.
64 bytes from a.root-servers.net (198.41.0.4): icmp_seq=1 ttl=53 time=47.2 ms

--- a.root-servers.net ping statistics ---
1 packets transmitted, 1 received, 0% packet loss, time 0ms
rtt min/avg/max/mdev = 47.160/47.160/47.160/0.000 ms
PING a.root-servers.net.(a.root-servers.net (2001:503:ba3e::2:30)) 56 data bytes
64 bytes from a.root-servers.net (2001:503:ba3e::2:30): icmp_seq=1 ttl=56 time=66.2 ms

--- a.root-servers.net. ping statistics ---
1 packets transmitted, 1 received, 0% packet loss, time 0ms
rtt min/avg/max/mdev = 66.156/66.156/66.156/0.000 ms
ar@cello ~ %
ar@cello ~ % zsh -c '
fqdn=oboe.murbly.net
echo -n A:    ; host -t A $fqdn
echo -n AAAA: ; host -t AAAA $fqdn
echo sorry for $SHELL syntax btw;
integer succ=0
integer fail=0
integer mixed=0
integer samplesz=100
repeat $samplesz; do
    host oboe.murbly.net >/tmp/yy
      grep -q IPv6 /tmp/yy && ! grep -q NXDOMAIN /tmp/yy && (( succ++ ))
    ! grep -q IPv6 /tmp/yy &&   grep -q NXDOMAIN /tmp/yy && (( fail++ ))
      grep -q IPv6 /tmp/yy &&   grep -q NXDOMAIN /tmp/yy && (( mixed++ ))
done; echo "Out of $samplesz attempts: $succ desired outcomes, $fail shitty outcomes, $mixed mixed outcomes"
'
A:oboe.murbly.net has no A record
AAAA:oboe.murbly.net has IPv6 address 2a00:f480:8:d::b0e:0
sorry for /usr/bin/zsh syntax btw
Out of 100 attempts: 73 desired outcomes, 18 shitty outcomes, 9 mixed outcomes
ar@cello ~ %