smtp in IIS7--unable to connect successfully to the destination



I installed SMTP in IIS 7 on windows 2008,and use the default outgoing mail
virtual server in IIS 6 to send mail.
there are two ethernet adapter in the server,one to
internet(192.168.2.60),one for cluster.
for the mail virtual server,
properities-->general-->the ip address is 192.168.2.60,
access-->relay restrictions-->all except the list below
delivery-->outbound security-->anonymous
if telnet 192.168.2.60 25
send a mail to hotmail.com,it response:
Unable to deliver message to the following recipients, due to being unable
to connect successfully to the destination mail server.

username@xxxxxxxxxxx

--9B095B5ADSN=_01C96A41E70D183000000010nanlbcluster1n1.
Content-Type: message/delivery-status

Reporting-MTA: dns;nanlbcluster1n1.na.it
Received-From-MTA: dns;
Arrival-Date: Tue, 30 Dec 2008 00:56:00 -0500

Final-Recipient: rfc822;username@xxxxxxxxxxx
Action: failed
Status: 4.4.7

and when use the smtpdiag,all passed and successfully connect to hotmail.com

and I've closed the firewall in win 2008.

and also nat public ip for the 25 port of 192.168.2.60

could you help me?
thanks a lot


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