Fernando Gozalo:
> Hi,
>
> does the postfix smtp client implement the IPv6 to IPv4 fallback
> mechanism as browsers do?
Postfix implements the MX fallback strategy as defined in the SMTP
RFC (5321). In addition, Postfix implements this:
smtp_address_preference (default: any)
The address type ("ipv6", "ipv4" or "any") that the Postfix SMTP client
will try first, when a destination has IPv6 and IPv4 addresses with
equal MX preference. This feature has no effect unless the inet_proto-
cols setting enables both IPv4 and IPv6. With Postfix 2.8 the default
is "ipv6".
This feature is available in Postfix 2.8 and later.
Wietse
