Rémi Denis-Courmont wrote:
Hello,
Le Lundi 29 Mai 2006 13:23, Arifumi Matsumoto a écrit :
- Teredo is defined. (RFC4380)
Teredo should have less priority than 6to4 and IPv4
considering its communication overhead and reliability ?
Also, this value below conforms to Windows.
I pretty much agree that Teredo should have a lower priority than public
IPv4 space, but it is not so obvious with regards to private or
link-local IPv4 addresses... in the client to server case were NAT are
a non-issue, using IPv4 is better anyway, but in other cases (e.g. SIP
calls, p2p...), it will probably be worse.
- ULA should have less precedence than IPv4.
As brought up by Pekka Savola, ULA is a possible cause
of connection failure. It gets worse, as IPv6 deployment
proceeds and more FQDNs have both A and AAAA records.
As a few people already pointed out, I guess it's not
so easy to solve the Pekka's ULA and IPv4 trouble other
than to change policy table. While the problems caused
by prioritizing ULA lower than IPv4 seem to be relatively
easily solved. For example, by removing A record, using
DNS zone-split, like that.
As with Teredo, it should at least be safe to underprioritize ULAs
against public IPv4 space, but if I understand correctly, that implies
adding 4 extra IPv4 rules (3 for RFC1918, and one for 169.154/16). And,
yeah, I can't think of any safe choice in between private IPv4 and
ULAs.
It's better if you can control on/off of temporary address.
It's much better if you can control which address to use
for which service. IMHO, Policy Table is the best place
to implement this additional function.
Similarly, it might (?) be nice to have a (IPv4) NAT-friendly
application profile and a NAT-unfriendly one, though they might be
caveats that I've not thought of.
I think it's impossible to find defaults that fit all. We should have a
sensible default, and I think some minor changes should be made, but IMO
there may be many cases where this needs to be configured to match
individual site preferences.
Stig
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