使用 telnet 加上 auth 寄信

telnet xx.xx.xx.xx 25 # 輸入， telnet 到 25 port
Trying xx.xx.xx.xx…
Connected to xx.xx.xx.xx.
Escape character is ‘^]’.
220 xx.xx.xx.xx ESMTP Service, Version: xx — ready at 01/16/10 01:50:14
ehlo wow   # 輸入，helo 一下
250-home [dd.dd.dd.dd], this server offers 4 extensions
250-AUTH LOGIN
250-SIZE 10485760
250-HELP
250 AUTH=LOGIN # 可以看到它可以使用 login 認證
auth login             # 輸入
334 VXNlcm5hbWU6
Y3Jvc3NAc3NvcmMubmV0   # 輸入，這個是 email 帳號經過base64編碼
334 UGFzc3dvcmQ6
cXdlMTIzNDU=                     # 輸入，這個是 email 密碼經過base64編碼
235 Authenticated            # 認證成功
mail from: [email protected]   # 輸入，寄件者
250 Requested mail action okay, completed
rcpt to:[email protected]         # 輸入，收件者
250 Requested mail action okay, completed
data         # 輸入，信件內容開始
354 Start mail input; end with <CRLF>.<CRLF>
From: [email protected]      # 輸入，寄件者
To: [email protected]         # 輸入，寄件者
Subject: wow               # 輸入，主旨
123                           # 輸入，信件內容
.                                 # 輸入，結尾
250 Requested mail action okay, completed
quit                        # 輸入，跳出
221 Service closing transmission channel
Connection closed by foreign host.