ann kok wrote:
How to configure the mail server to put the code before sending out the mail? eg: When I send out the mail to yahoo to some receiver's address, it needs me to put the number and letter as same as the box before sending out the mail
I think you are mixing "sending mail via a mailserver" and "sending a mail over a web interface". When using a mailserver you do not need to enter any captchas (which I think is what you mean by code), you just send your mail to the correct mailserver.
Ralph