spam mail

[mk001]

i use exchange 2000 and trendmicro scanmail. i found that there have been many aaaxxxx@mydomain.com(mydomain.com is create by me. however, aaaxxxx is not email account in my exchange 2000) come to exchange 2000.

how to prevent the external user to send this fake mail to my exchange 2000?

i had set closed relay in smtp and disable NDR.

thanks.

 

[Zelandakh]

Look at SPF records / Sender Policy Framework.