我用socket写了一个邮件发送程序，没有使用其他包，下面是错误内容，加粗的部分是发送的信息，好像是邮件发送者没有通过验证，应该如何在程序中验证呢？220 163.com Anti-spam GT for Coremail System (163com[20111010])
HELO jia1546-PC
250 OK
MAIL FROM: <[email protected]>
553 authentication is required,smtp3,DdGowEDZqWXjSIFPfOQxHQ--.258S2 1333872868
RCPT TO: <[email protected]>
503 bad sequence of commands
DATA
503 bad sequence of commands
hello
HELO jia1546-PC
250 OK
MAIL FROM: <[email protected]>
553 authentication is required,smtp3,DdGowEDZqWXjSIFPfOQxHQ--.258S2 1333872868
RCPT TO: <[email protected]>
503 bad sequence of commands
DATA
503 bad sequence of commands
hello
发邮件可以用很多其他组件的