The remote DNS server may be affected by a denial of service vulnerability
The remote host is running Bind, a popular name server. Versions of BIND earlier than 9.8.4-P1 / 9.9.2-P1 are potentially affected by a denial of service vulnerability. Affected versions of BIND can be forced to crash via malicously crafted DNS request. Note that this vulnerability only affects installs using the 'dns64' configuration option
Upgrade to BIND 9.8.4-P1 / 9.9.2-P1 or later. Alternatively, disable DNS64 functionality via configuration options.