mail就是 gem install mail
程序就是个很简单的示例，错误贴在下面，我试过用管理员权限运行，应该不是权限的问题
C:/Ruby200/lib/ruby/2.0.0/net/smtp.rb:540:in `initialize': No connection could be made because the target machine actively refused it. - connect(2) (Errno::ECONNREFUSED)
from C:/Ruby200/lib/ruby/2.0.0/net/smtp.rb:540:in `open'
from C:/Ruby200/lib/ruby/2.0.0/net/smtp.rb:540:in `tcp_socket'
from C:/Ruby200/lib/ruby/2.0.0/net/smtp.rb:550:in `block in do_start'
from C:/Ruby200/lib/ruby/2.0.0/timeout.rb:66:in `timeout'
from C:/Ruby200/lib/ruby/2.0.0/net/smtp.rb:549:in `do_start'
from C:/Ruby200/lib/ruby/2.0.0/net/smtp.rb:519:in `start'
from C:/Ruby200/lib/ruby/gems/2.0.0/gems/mail-2.5.4/lib/mail/network/delivery_methods/smtp.rb:112:in `deliver!'
from C:/Ruby200/lib/ruby/gems/2.0.0/gems/mail-2.5.4/lib/mail/message.rb:248:in `deliver!'
from r.rb:10:in `<main>'

在debian下倒是能运行，不过邮件没法出去，迟一些再看看