At 08:14 06-01-2008, Iljitsch van Beijnum wrote:
Not sure what you mean here by "SMTP clients"... Would that be client
computers such as the one I'm typing this message on? But those don't
look at MX records, unless I'm very much mistaken.
What you are using to send this message is known as a MUA (Mail User
Agent). In RFC 821, the two hosts participating in an SMTP
transaction were described as the "SMTP-sender" and
"SMTP-receiver". Nowadays they are referred to as "SMTP client" and
Quoting RFC 2821, an SMTP client determines the address of an
appropriate host running an SMTP server by resolving a destination
domain name to either an intermediate MX host or a final target host.
No, the part that doesn't make sense is enabling IPv6 but then
preferring IPv4. That way, you don't get to find out what works and
what doesn't work. It is true that enabling (and thus preferring) IPv6
can have downsides. In my case it means the IETF website is
Agreed. However, finding out what works and what doesn't work might
not be an alternative in a production environment as it would have a
significant impact on mail delivery.
Ietf mailing list