telnet命令测试邮件服务器连通性telnet mailaws.swiretest.com 25helo mailaws.swiretest.commail from:<test@test.com>rcpt to:<test@test.com>data必须一次输入正确，没有回退机会每输入一行都应该提示200 OK说明服务器和邮件服务器之间网络连通性没问题...