Using Xmanager to connect to remote CentOS 7 via XDMCP

Gnome in CentOS 7 tries to use local hardware acceleration and this becomes a problem when trying to connect remotely using XDMCP. To avoid this problem, you have to use an alternative display manager (other than ‘gdm’) and desktop environment.

This guide explains how you can change the display manager to lightdm from gdm and desktop environment from Gnome to Xfce.

Switching display manager from gdm to lightdm

1. Add a new source repository:
   
2. Switch to root account:
   
3. Install lightdm:
   
4. Configure lightdm:
   
   
   If the lightdm.conf does not exist, create one.
5. Change the default display manager to lightdm:
   
6. Stop gdm and start lightdm:
   
7. Disable firewall to test connection. It is recommended that you only allow incoming UDP port 177.
   

Add Xfce and configure as the default desktop environment.

1. Add a new source repository:
   (If you already installed EPEL repository, this is not required.)
   
2. Install an alternative desktop environment:
   
3. Restart lightdm:
   
4. Connect with Xmanager and select Xfce.