所以 telnet 实际上正在工作，我的意思是 telnet localhost 25 正在连接；但是 telnet localhost 或 telnet localhost 9000 得到了这样的结果：
Trying 127.0.0.1...
telnet: Unable to connect to remote host: Connection refused
nmap 结果：
$ nmap localhost
Starting Nmap 6.00 ( http://nmap.org ) at 2013-10-03 00:54 MSK
Nmap scan report for localhost (127.0.0.1)
Host is up (0.00030s latency).
rDNS record for 127.0.0.1: localhost.localdomain
Not shown: 992 closed ports
PORT STATE SERVICE
22/tcp open ssh
25/tcp open smtp
80/tcp open http
587/tcp open submission
631/tcp open ipp
3306/tcp …hadoop ×1