On Wed, 16 Apr 2008, Willie Gillespie wrote:
Tony Finch wrote:
On Wed, 16 Apr 2008, Ned Freed wrote:
I doubt that it makes sense to accept email from
on a system that can only communicate with IPv4 addresses.
I foresee some company setting up an IPv6 to IPv4 e-mail relay for
individuals or other companies that only have IPv6 addresses.
I agree with John that this is likely to happen.
For an IPv4-only receiving system, would this appear as an e-mail from
test(_at_)ipv6(_dot_)l(_dot_)google(_dot_)com (even though it comes over the
IPv4 link)? At
that point, would it make sense to accept the message?
The sender's relay has to be two-way, so the IPv6-only site's MXs would
have to refer to the relay's IPv4 address as well as the site's own IPv6
address. Then the sender's email addresses can be verified successfully by
I don't think John is right to expect IPv4-only recipient sites to obtain
a 4-to-6 SMTP relay service any time soon. IPv6 sites will have to deal
with the interop burden until v4 is the minority.
For example, there are likely to be problems if
AAAA-only addresses leak out, and these are likely to be worse than the
problems that A-only addresses like apache(_at_)www(_dot_)example(_dot_)com
f.anthony.n.finch <dot(_at_)dotat(_dot_)at> http://dotat.at/
BISCAY FITZROY: CYCLONIC 5 TO 7, OCCASIONALLY GALE 8, PERHAPS SEVERE GALE 9
LATER. ROUGH OR VERY ROUGH. RAIN OR SQUALLY SHOWERS. MODERATE OR GOOD,