3.5 IPv6 DNS Operation with BIND 279
for Solaris). On BSD variants and Linux, IPV6_RECVPKTINFO is not effective for IPv4 packets
received on the AF_INET6 socket and the query is dropped at an early stage of the query
examination procedure of named.
The authors emphasized the risk of relying on IPv4-mapped IPv6 addresses in applications
in Chapter 7 of IPv6 Core Protocols Implementation. All the above issues should prove that the
concerns are real. Fortunately, the IPV6_V6ONLY socket option provides a perfect solution
to these problems. The recommended solution for DNS operators who want to use IPv6 is
thus to use a newer version of BIND9—9.3 or later. As explained above, newer versions of
named enable this socket option for AF_INET6 sockets. In addition, ...