Does `ping www.heise.de` from the same host work? Does `check_ping -4 -H www.heise.de -w '200,20%' -c '500,50%'` solve the problem?
Either way, you might want to use `check_icmp` (which currently doesn't support ICMPv6) to work around the issue (and because it's preferable for v4 checks anyway). -- Reply to this email on GitHub: https://github.com/monitoring-plugins/monitoring-plugins/issues/1397#issuecomment-161086657
