>>726
試しにtelnetで送信してみると、
telnet mx1.hotmail.com 25
Trying 65.54.244.8...
Connected to mx1.hotmail.com (65.54.244.8).
Escape character is '^]'.
220 bay0-mc1-f15.bay0.hotmail.com Sending unsolicited
commercial or bulk e-mail to Microsoft's computer network is
prohibited. Other restrictions are found at http://privacy.msn.com/Anti-spam/.
Violations will result in use of equipment located in California and other states. Thu, 5 Jun 2008 20:05:23 -0700
helo hogehoge.jp
250 bay0-mc1-f15.bay0.hotmail.com (3.6.0.91) Hello [xxx.xxx.xxx.xxx]
mail from: webmaster@hogehoge.jp
250 webmaster@hogehoge.jp....Sender OK
rcpt to: hogehoge@msn.com
250 hogehoge@msn.com

data
354 Start mail input; end with <CRLF>.<CRLF>
subject: test mail

this is the test mail
.
250 <BAY0-MC1-F15V1eQoML0005d413@bay0-mc1-f15.bay0.hotmail.com> Queued mail for delivery

と出て、送信は完了しているように見えますが、実際には届きません。
hogehoge@msn.comが実際に送りたい宛先です。