Tribblix: manual page: filter-aaaa.8

FILTER-AAAA(8) BIND 9 FILTER-AAAA(8)

NAME

filter-aaaa - filter AAAA in DNS responses when A is present

SYNOPSIS

plugin query "filter-aaaa.so" [{ parameters }];

DESCRIPTION

filter-aaaa.so is a query plugin module for named, enabling named to
omit some IPv6 addresses when responding to clients.

Until BIND 9.12, this feature was implemented natively in named and
enabled with the filter-aaaa ACL and the filter-aaaa-on-v4 and
filter-aaaa-on-v6 options. These options are now deprecated in
named.conf but can be passed as parameters to the filter-aaaa.so
plugin, for example:

plugin query "filter-aaaa.so" {
filter-aaaa-on-v4 yes;
filter-aaaa-on-v6 yes;
filter-aaaa { 192.0.2.1; 2001:db8:2::1; };
};

This module is intended to aid transition from IPv4 to IPv6 by
withholding IPv6 addresses from DNS clients which are not connected
to the IPv6 Internet, when the name being looked up has an IPv4
address available. Use of this module is not recommended unless
absolutely necessary.

Note: This mechanism can erroneously cause other servers not to give
AAAA records to their clients. If a recursing server with both IPv6
and IPv4 network connections queries an authoritative server using
this mechanism via IPv4, it is denied AAAA records even if its client
is using IPv6.

OPTIONS

filter-aaaa
This option specifies a list of client addresses for which
AAAA filtering is to be applied. The default is any.

filter-aaaa-on-v4
If set to yes, this option indicates that the DNS client is at
an IPv4 address, in filter-aaaa. If the response does not
include DNSSEC signatures, then all AAAA records are deleted
from the response. This filtering applies to all responses,
not only authoritative ones.

If set to break-dnssec, then AAAA records are deleted even
when DNSSEC is enabled. As suggested by the name, this causes
the response to fail to verify, because the DNSSEC protocol is
designed to detect deletions.

This mechanism can erroneously cause other servers not to give
AAAA records to their clients. If a recursing server with both
IPv6 and IPv4 network connections queries an authoritative
server using this mechanism via IPv4, it is denied AAAA
records even if its client is using IPv6.

filter-aaaa-on-v6
This option is identical to filter-aaaa-on-v4, except that it
filters AAAA responses to queries from IPv6 clients instead of
IPv4 clients. To filter all responses, set both options to
yes.

AUTHOR

Internet Systems Consortium

COPYRIGHT