Home / ubuntu / Questions / 1034057
In Process
chris_asn
Asked: 2018-05-10 05:48:13 +0800 CST

(closed) Configuring and using Xdmcp with gdm3 on ubuntu 18.04

  • 772

On a fresh minimal ubuntu 18.04 installation, I tried to activate and use the gdm3 xdmcp server.

Here are steps I followed:

  • Installation

I used the normal installation.

"Download updates during installation" was checked

"Install 3rd parties for Gfx/Wifi/.." was not checked.

  • Xdmcp server

1 . Edit /etc/hosts.allow to set (cf. Gnome doc.).

ALL: ALL #Wide opened to be sure the problem isn't here

2 . Edit /etc/gdm3/custom.conf to set:

[security] DisallowTCP=false [xdmcp] Enable=true

3 . Restart gdm

sudo /etc/init.d/gdm3 restart

  • Xdmcp client

sudo apt install xnest Xnest -query localhost -geometry 1024x768 :1

Unfortunately, I only have a black screen with regular white flash.

Where did I do something wrong ?

Thanks for your help.

Christophe C.

gdm xdmcp 18.04

2 Answers

  1. In case soemone else finds this question and has problems getting XDMCP to work with gdm3, I managed to get it working by setting gdm3 to use xorg instead of wayland.

    /etc/gdm3/custom.conf

    [daemon]
# Uncoment the line below to force the login screen to use Xorg
WaylandEnable=false
    • 1

  2. Sorry to post many months after my initial question but I prefered to confirm my results.

    Here they are:

    Working solutions or workarrounds

    • Debian 10.3 xdmcp access with lightdm & LxQT

       /usr/share/lightdm/lightdm.conf.d/50-remote-session.conf

 [SeatDefaults]
 xserver-allow-tcp=true
 [XDMCPServer]
 enabled=true

    • Ubuntu 20.4 x2go access with LxQT

    Not working solutions

    • Ubuntu 20.4 xdmcp access with gdm3 & LxQT

       I did many tries (including the Pathin tip about wayland) under
 18.4 and now... 20.4.

    • Ubuntu 20.4 xdmcp access with lightdm & LxQT

       I unsuccessfully tried the "lightdm.conf.d/50-remote-session.conf"
 change validated under debian.

    Due to problems I had with xdmcp, I am now using different alternatives to connect remotly.

    I hope my tests will help someone.

    • 1