What were you trying to do that didn't work?

After setting "DisallowTCP=false" in /etc/gdm/custom.conf and restarting GDM, -nolisten tcp is still set for sessions of GNOME. 

What is the impact of this issue to you?

Unable to open TCP traffic for applications that require communicating via TCP traffic through Xorg.

Please provide the package NVR for which the bug is seen:

gdm-40.1-27.el9.x86_64

xorg-x11-server-Xorg-1.20.11-26.el9.x86_64

How reproducible is this bug?:

I was able to consistently reproduce the behavior.

Steps to reproduce

1.  Edit /etc/gdm/custom.conf to have DisallowTCP=false set under "[daemon]"
2. Restart GDM
3. Observe Behavior.

Expected results

TCP traffic allowed when option is set.

Actual results

TCP traffic is still not allowed after setting option to allow it.