Reg: IPv6 dual stack

hai_manish · ‎11-19-2007

Hi,

Suppose i have configured IPv6 in my network and i have configured dual stack on my server. If any client from outside network tries contacting my server with the hostname then DNS will resolve which IP (IPv4 of IPv6) for my server. both of my server's ip will be there in DNS entry or it'll be one of them. If both then which ip (IPv4 or IPv6) it'll give.What is the selection crieteria for this in DNS.

Pls refer me few links also related to DNS entries for IPv6.

Regards,

Joe Clarke · ‎11-19-2007

It really depends on how your application works. If the app requests a AAAA record first, and that succeeds, the client will attempt to contact the server via IPv6. If, however, the client only requests the A record, then the client will communicate with the server with IPv4.

In C programming, one could use gethostbyname2(), getaddrinfo(), or getnameinfo() to specifically request an address of type AF_INET6. Some resolver libraries can even be configured to use IPv6 by default (e.g. on FreeBSD or Linux one can add "options inet6" to /etc/resolv.conf).