为了防止邮件服务器变成垃圾邮件转发服务器,现在架设在 Interent 上的绝大多数邮件服务器都开设了发信认证功能。检测方法如下: C:\>telnet 119.119.119.212 25 Trying 119.119.119.212... Connected to 119.119.119.212. Escape character is '^]'. 220 steven.chinanusa.local Winmail Mail Server ESMTP ready ehlo 250-steven.chinanusa.local Winmail Mail Server 250-PIPELINING 250-AUTH=NTLM LOGIN PLAIN 250-AUTH NTLM LOGIN PLAIN 250-STARTTLS 250-SIZE 5242880 250 8BITMIME mail from: steven@abcdefg123.com (输入一个非本系统中用户的邮件地址) 250 ok rcpt to: steven@abcdefg123.com (输入一个非本系统中用户的邮件地址) 553 sorry, you don't authenticate or the domain isn't in my list of allowed rcpthosts(#5.7.1) quit 221 steven.chinanusa.local Winmail Mail Server Connection closed by foreign host. C:\> 如果上述输入 rcpt to 命令后,出现 553 sorry, you don't authenticate or the domain isn't in my list of allowed rcpthosts(#5.7.1) 错误信息就表示系统是需要认证的。