转为root，
yum install firefox
但是随即出现问题：
(firefox:4871): GnomeUI-WARNING **: While connecting to session manager:
None of the authentication protocols specified are supported.
/usr/lib/firefox/firefox: symbol lookup error: /usr/lib/libgdk-x11-2.0.so.0: undefined symbol: _XGetRequest
yum真不是个好东西。。。
google被墙，百度找不到，辗转到yahoo日本去找。
找到：
Problem With VNC refreshing (Centos 6.2) - nixCraft Linux / UNIX ...
- このページを和訳
nixcraft.com/.../19976-Problem-With-VNC-refreshing-(Centos... - キャッシュ
/usr/bin/gnome-session: symbol lookup error: /usr/lib64/libgdk-x11-2.0.so.0: undefined symbol: _XGetRequest (nautilus:17444): EggSMClient-WARNING **: Failed to connect to the session manager: IO error occured opening ...
地址：http://nixcraft.com/showthread.php/19976-Problem-With-VNC-refreshing-(Centos-6-2)
正文太长懒得看，反正有一样的错误，直接看解决方案：
Solved
I figrued out what was going wrong. After looking into the log file and finding that error message, I was able to deduce that I need to upade xlibs. Once this was done everything worked fine.
For anyone that runs into this issue run this command:yum install libX11
解决。
