Thanks for your pro advices, but I found out that the problem cause by my adsl modem! Actually, I forgot to config NAT after resetting my adsl modem. I've reconfiged it all and it seem worked well.
But, by the way, there a little problem should be concerned.
I can received e-mail from outside just fine, but when I sent out a mail, it seemed not be delivered by the recipient, even I saw it in the "Sent Items" folder and there's no error message about the failure delivery.
Then, I've used the Tracking message of Exchange Server Manager, it appeared like: "Non-Delivered Report(NDR) was generated" in the tracking log. But I didn't received any of this report at all.
Any ideas about this?
First come, last serve