xdmcp server ubuntu 14.04 login error

[James Anderson]

xdmcp server ubuntu 14.04 LTS
Client side displays server log in screen correctly, however when a user name is selected or manually entered the server will not accept any password, displays authentication error and returns to main log in screen

I believe it is a configuration file issue on the server side, not sure which configuration file though.
I have tried remmina and xepher from a client Ubuntu 14.04 LTS with same results.

 apt-cache policy xdm
xdm:
  Installed: (none)
  Candidate: 1:1.1.11-1ubuntu1
  Version table:
     1:1.1.11-1ubuntu1 0
        500 http://us.archive.ubuntu.com/ubuntu/ trusty/universe amd64 Packages

[James Anderson (jim-255)]

Just tried going the other way, just setting

[XDMCPServer]
enabled=true

on the 'workstation' computer and attempting to login from the server.
got exactly the same result.

Something else is missing and I'm not sure what that is.

[James Anderson (jim-255)]

Not sure weather it's a GDM OR XDM issue, judging from other issues found it looks like it's a previous GDM bug resurfaced!

[James Anderson (jim-255)]

Further experimentation resulted in a workaround.
I switched from GDM to LIGHTDM
Configured lightdm the same as for Ubuntu 12.04
XDMCP works as documented.
I can now login to the server from any thin client terminal.

[Michael Plotkin (plotkin)]

Hello, I am also affected by this bug - cannot login using any and all XDMCP clients that I know of into my server running Ubuntu 14.04. I am reluctant to switch to lightdm from gdm for a variety of reasons. I also would like to understand how active this bug is. It seems to me that if it's a "real" bug it should affect quite a lot of people - not just 2 of us. Or are we doing something wrong in the sense of not configuring something correctly.
Thank you,
Michael.