On Tue, 31 Oct 2006, Edward Lewis wrote: > At 16:34 +0000 10/31/06, Jeroen Massar wrote: > > >Like any IPv4 -> IPv6 transition mechanism: first try IPv6, then try IPv4. > > There is the option to try both simultaneously. A query for the A RR can be > sent in parallel to the AAAA RR. This is better from the point of view of the > application user, there isn't a need to wait for a time out. On the other > hand, this makes the application developer's job harder - having to juggle two > potential answers and connections starting up (assuming TCP).
Note that the original question was about which DNS _server_ to query first, not which RR type to query first. I believe most implementations send the queries in the order the servers have been listed in /etc/resolv.conf or equivalent, and this decision algorithm doesn't care whether the address is v4 or v6. As for the latter issue, RFC 4472 section 5.1 discusses this a bit. -- Pekka Savola "You each name yourselves king, yet the Netcore Oy kingdom bleeds." Systems. Networks. Security. -- George R.R. Martin: A Clash of Kings . dnsop resources:_____________________________________________________ web user interface: http://darkwing.uoregon.edu/~llynch/dnsop.html mhonarc archive: http://darkwing.uoregon.edu/~llynch/dnsop/index.html
