At 4:58 PM +0800 11/1/06, Blue wrote:
Hi,
For statically and manually configured DNS server list, the resolver won't
have problems in choosing IPv4/IPv6 servers. Like you've said, the sequence
is supposed to be based on the configuration file. However, when we have
dynamic DNS v4/v6 server list from DHCPv4/DHCPv6, the resolver needs to
decide which server to request first.
BR,
Yi-Wen
In this case, my answer would be a bit different from what I wrote
earlier. If it is a matter of which transport is used for a stub
resolver (something that reads a static list) to reach a local name
server, then the administrator should configure using the more stable
transport first. An administrator can judge that as usually you are
only traversing one network from stub to local name server. If the
administrator wants to shift traffic to IPv6, then that is configured
first.
To clarify my previous messages - the reason I talk about retrieving
address records is that before you can reach a server you have to
have the address records. When an NS record is read and you get the
domain name, you have the choice to ask for one or the other, or both
address types. From that you open transport points (ports in UDP).
If you only get the AAAA record, you can't try the IPv4 transport.
I am not trying to discourage the use of IPv6 through my disagreement
with trying "IPv6 first, IPv4 second." In my experience with the
state of IPv6 routing across a wide area, the IPv6 backbone (such as
it is) is still in being formed. And until there is an authoritative
AAAA in the root-servers.net zone for any of the root servers the DNS
(system) is still "fractured" in IPv6 space. (As in, you have to go
through IPv4 to get anywhere.)
--
-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-
Edward Lewis +1-571-434-5468
NeuStar
Secrets of Success #107: Why arrive at 7am for the good parking space?
Come in at 11am while the early birds drive out to lunch.
.
dnsop resources:_____________________________________________________
web user interface: http://darkwing.uoregon.edu/~llynch/dnsop.html
mhonarc archive: http://darkwing.uoregon.edu/~llynch/dnsop/index.html
