[root@zbmail ~]# telnet localhost 25
Trying ::1...
Connected to localhost.
Escape character is '^]'.
220 mail.xx.com ESMTP Postfix
。。。。。。
这在邮件服务器上测试时正常的
但是我在其他服务器上telnet这个邮件服务器会显示超时
[root@iZ942yn9r7wZ ~]# telnet mail.xx.com 25
Trying x.x.x.x...
telnet: connect to address x.x.x.x: Connection timed out
请问这怎么办