On Mar 19, 2008, at 14:42, Alexander Mayrhofer wrote: > - I wonder whether 2.3 should include some text suggesting that the > preference of A vs. AAAA records could also depend on the transport > protocol over which the query was received?
No. Absolutely not. If any text is to be added here it must say the exact opposite. ie The transport protocol used to deliver a query/ response MUST NOT be used to make assumptions about whether the client prefers A or AAAA records. If this assumption was made, it would violate the end-to-end principle. And potentially the basic principle of universal response from the DNS since a query over IPv6 might just get AAAA records and one over IPv4 only gets A records. Besides, the transport service used to send the query has no bearing on the transport service used to make the original request. Suppose my IPv6 client speaks IPv6 to the local dual stack resolving server. It sends the queries to an authoritative server over IPv4. That server then suppresses the AAAA records because it thinks the query is only interested in IPv4, so my client never gets to find out that the host it wanted to contact was is reachable over IPv6 or even has an IPv6 address. _______________________________________________ DNSOP mailing list DNSOP@ietf.org https://www.ietf.org/mailman/listinfo/dnsop
