XDMCP connection fails

XDMCP connection fails 

1）修改檔案 /etc/inittab file 設定 runlevel 5
id:5:initdefault:

2）GDM configuration (When the Linux is using gdm)
/etc/X11/gdm/gdm.conf
（rhel 6 修改此檔案 /etc/gdm/custom.conf）
設定：
[xdmcp]
Enable=1

3）KDM configuration (When the Linux is using kdm)
Open /etc/X11/xdm/xdm-config file. 
Comment out "requestPort" option as following:
DisplayManager.requestPort: 0
==>
!DisplayManager.requestPort: 0 


Open /etc/X11/xdm/Xaccess file. 
Remove the initial "#" character for the following line:
#* #any host can get a login window
==>
* #any host can get a login window 

4）關閉防火牆 
Firewall configuration (If the firewall has been configured)
Open /etc/sysconfig/ipchains file. 
Add the following lines at the top of the file:
-A input -p udp -s 0/0 -d 0/0 177 -j ACCEPT
-A input -p tcp -s 0/0 -d 0/0 telnet -j ACCEPT
-A input -p tcp -s 0/0 -d 0/0 ssh -j ACCEPT
-A input -p tcp -s 0/0 -d 0/0 login -j ACCEPT
-A input -p tcp -s 0/0 -d 0/0 exec -j ACCEPT
-A input -p tcp -s 0/0 -d 0/0 shell -j ACCEPT
-A input -p tcp -s 0/0 -d 0/0 7100 -j ACCEPT