Mailer configuration - IPv6 only

[paul%whooppee.com@localhost]

I'm trying to set up my home machine for receiving Email.  The machine
has only IPv6 fixed address (IPv4 connectivity is via NAT).

I've set up my DNS correctly (I think!) and I have a dual-stack machine
running as a backup-MX, in case there's a sender that cannot speak v6.

;; ANSWER SECTION:
whooppee.com.           599     IN      MX      50 vps1.whooppee.com.
whooppee.com.           599     IN      MX      40 pokey.whooppee.com.

(pokey is the desired mail destination, with IPv6 only;  vps1 is the
backup machine with both v4 and v6)

And I've confirmed that postfix is listening:

# netstat -a -f inet6 | grep smtp
tcp6       0      0  *.smtp                 *.*                LISTEN


However, for some reason, all email is still being delivered to the
backup machine, even when being delivered via IPv6.  According to
/var/log/maillog on the desired machine, there aren't even any
connection attempts.  (The only mail being delivered to the desired
machine is locally-originated mail.)

Have I done something wrong?  Have I forgotten something?  Or does
anyone have a clue on how to make this work?

(FWIW, once I get reliable delivery to the desired IPv6-only machine,
I intend to change the postfix config on the backup machine to act as
a relay, rather than a final destination.)


+------------------+--------------------------+------------------------+
| Paul Goyette     | PGP Key fingerprint:     | E-mail addresses:      |
| (Retired)        | FA29 0E3B 35AF E8AE 6651 | paul at whooppee.com   |
| Kernel Developer | 0786 F758 55DE 53BA 7731 | pgoyette at netbsd.org |
+------------------+--------------------------+------------------------+