例如:
mail("webmaster@mistruster.com,mistruster@263.net", "测试邮件", "This is a test.", "From: Webmaster@mistruster.com\nContent-Type:text/html;charset=gb2312;\n");
----- Transcript of session follows -----
... while talking to [127.0.0.1]:
>>> DATA
<<< 550 5.1.1 <ccc@ddd.com>... User unknown
550 5.1.1 ccc@ddd.com... User unknown
<<< 503 5.0.0 Need RCPT (recipient)