Ubuntu使用ftp命令下载文件停止不动解决方法

在Ubuntu 12.04中使用ftp命令下载文件，每次都停在150就不动了：

root@zyqpc:/# ftp 192.168.0.111
Connected to 192.168.0.111.
220 Serv-U FTP Server v6.4 for WinSock ready...
Name (192.168.0.111:zyq): zyq
331 User name okay, need password.
Password:
230 User logged in, proceed.
Remote system type is UNIX.
Using binary mode to transfer files.
ftp> get index.htm /home/zyq/index.htm
local: /home/zyq/index.htm remote: index.htm
200 PORT Command successful.
150 Opening BINARY mode data connection for index.htm (397 Bytes).

在Q群网友提醒下，开启被动传输模式，再测试就正常了：

ftp> passive
Passive mode on.
ftp> get index.htm /home/zyq/index.htm
local: /home/zyq/index.htm remote: index.htm
227 Entering Passive Mode (192,168,0,111,19,146)
150 Opening BINARY mode data connection for index.htm (397 Bytes).
226 Transfer complete.
397 bytes received in 0.00 secs (232.2 kB/s)
ftp>