Release Notes for BIND Version 9.11.12


BIND 9.11 (Extended Support Version) is a stable branch of BIND. This document summarizes significant changes since the last production release on that branch.

Please see the file CHANGES for a more detailed list of changes and bug fixes.


The latest versions of BIND 9 software can always be found at There you will find additional information about each release, source code, and pre-compiled versions for Microsoft Windows operating systems.

License Change

With the release of BIND 9.11.0, ISC changed to the open source license for BIND from the ISC license to the Mozilla Public License (MPL 2.0).

The MPL-2.0 license requires that if you make changes to licensed software (e.g. BIND) and distribute them outside your organization, that you publish those changes under that same license. It does not require that you publish or disclose anything other than the changes you made to our software.

This requirement will not affect anyone who is using BIND, with or without modifications, without redistributing it, nor anyone redistributing it without changes. Therefore, this change will be without consequence for most individuals and organizations who are using BIND.

Those unsure whether or not the license change affects their use of BIND, or who wish to discuss how to comply with the license may contact ISC at

Security Fixes

  • A race condition could trigger an assertion failure when a large number of incoming packets were being rejected. This flaw is disclosed in CVE-2019-6471. [GL #942]

New Features

  • The new GeoIP2 API from MaxMind is now supported when BIND is compiled using configure --with-geoip2. The legacy GeoIP API can be used by compiling with configure --with-geoip instead. (Note that the databases for the legacy API are no longer maintained by MaxMind.)

    The default path to the GeoIP2 databases will be set based on the location of the libmaxminddb library; for example, if it is in /usr/local/lib, then the default path will be /usr/local/share/GeoIP. This value can be overridden in named.conf using the geoip-directory option.

    Some geoip ACL settings that were available with legacy GeoIP, including searches for netspeed, org, and three-letter ISO country codes, will no longer work when using GeoIP2. Supported GeoIP2 database types are country, city, domain, isp, and as. All of the databases support both IPv4 and IPv6 lookups. [GL #182]

  • A SipHash 2-4 based DNS Cookie (RFC 7873) algorithm has been added. [GL #605]

    If you are running multiple DNS Servers (different versions of BIND 9 or DNS server from multiple vendors) responding from the same IP address (anycast or load-balancing scenarios), you'll have to make sure that all the servers are configured with the same DNS Cookie algorithm and same Server Secret for the best performance.

  • DS records included in DNS referral messages can now be validated and cached immediately, reducing the number of queries needed for a DNSSEC validation. [GL #964]

Bug Fixes

  • Glue address records were not being returned in responses to root priming queries; this has been corrected. [GL #1092]

  • Interaction between DNS64 and RPZ No Data rule (CNAME *.) could cause unexpected results; this has been fixed. [GL #1106]

  • named-checkconf now checks DNS64 prefixes to ensure bits 64-71 are zero. [GL #1159]

  • named-checkconf could crash during configuration if configured to use "geoip continent" ACLs with legacy GeoIP. [GL #1163]

  • named-checkconf now correctly reports a missing dnstap-output option when dnstap is set. [GL #1136]

  • Handle ETIMEDOUT error on connect() with a non-blocking socket. [GL #1133]

End of Life

BIND 9.11 (Extended Support Version) will be supported until at least December, 2021.

See for details of ISC's software support policy.

Thank You

Thank you to everyone who assisted us in making this release possible. If you would like to contribute to ISC to assist us in continuing to make quality open source software, please visit our donations page at