当 postfix 连接到 FQDN dur.bounceme.net 时，它使用外部 IP 地址：
root@dur:~#
root@dur:~# tail /var/log/mail.log
Aug 28 04:39:45 dur postfix/master[6667]: terminating on signal 15
Aug 28 04:39:46 dur postfix/postfix-script[6781]: starting the Postfix mail system
Aug 28 04:39:46 dur postfix/master[6782]: daemon started -- version 2.9.1, configuration /etc/postfix
Aug 28 04:39:52 dur postfix/smtpd[6786]: connect from localhost[127.0.0.1]
Aug 28 04:40:37 dur postfix/smtpd[6786]: B92B518431A: client=localhost[127.0.0.1]
Aug 28 04:41:21 dur postfix/cleanup[6790]: B92B518431A: message-id=<[email protected]>
Aug 28 04:41:22 dur postfix/qmgr[6784]: B92B518431A: from=<[email protected]>, size=438, nrcpt=1 (queue active)
Aug 28 04:41:23 dur postfix/smtp[6792]: connect to dur.bounceme.net[70.71.113.158]:25: Connection refused
Aug 28 04:41:23 dur postfix/smtp[6792]: B92B518431A: to=<[email protected]>, relay=none, delay=62, delays=60/0.02/1.6/0, dsn=4.4.1, status=deferred (connect to dur.bounceme.net[70.71.113.158]:25: Connection refused)
Aug 28 04:41:26 dur postfix/smtpd[6786]: disconnect from localhost[127.0.0.1]
root@dur:~#
是什么导致 FQDN 出现这种行为？
我可以、应该、如何配置 dur.bounceme.net 以解析为 127.0.0.1？