642 lines
14 KiB
Markdown
642 lines
14 KiB
Markdown
# Oracle Linux XRDP Root Login and GNOME Terminal Incident Report
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## Document Information
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- **System:** `miclo-bangladesh-vm-5`
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- **Operating System:** Oracle Linux Server 8.10
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- **Environment:** Virtual Machine / OpenStack
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- **Affected Service:** XRDP / GNOME graphical remote access
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- **Incident Type:** Remote GUI session failure and GNOME Terminal startup failure
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- **Status:** Resolved
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- **Date:** 2026-08-17
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---
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## 1. Executive Summary
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An issue was identified on an Oracle Linux 8.10 virtual machine where SSH access was working, but graphical access through XRDP was unstable.
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The incident had two distinct symptoms:
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1. XRDP login using the `root` account authenticated successfully, but the graphical session closed immediately after login.
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2. After the root XRDP desktop was made operational, GNOME Terminal did not open even though other graphical applications and `xterm` worked.
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The investigation confirmed that networking, port 3389, XRDP authentication, TLS, Xorg, and the installed XRDP packages were functioning correctly.
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The first failure was caused by the XRDP window-manager startup path for the root account. XRDP was configured to use a per-user startup script named `startwm.sh`, but `/root/startwm.sh` did not exist. XRDP therefore used its default window-manager startup script, which did not correctly initialize the root GNOME session.
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The second failure was caused by an inconsistent D-Bus/systemd user-session environment. The GNOME desktop was running on the XRDP X11 display, but `gnome-terminal-server`, which is activated through the root user's D-Bus/systemd user environment, did not initially receive the correct `DISPLAY`, `XAUTHORITY`, and related session variables. As a result, GNOME Terminal failed with `status=10` and `Cannot open display`.
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The issue was resolved by creating a root-specific XRDP startup script, using the standard root user D-Bus at `/run/user/0/bus`, and propagating the XRDP X11 environment into the D-Bus/systemd user activation environment.
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---
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## 2. Initial Symptoms
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The server was reachable through SSH, but direct graphical access and XRDP access were problematic.
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System verification showed:
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```bash
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cat /etc/os-release
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```
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Result:
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```text
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NAME="Oracle Linux Server"
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VERSION="8.10"
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VERSION_ID="8.10"
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```
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The system was correctly configured to boot into graphical mode:
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```bash
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systemctl get-default
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```
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Result:
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```text
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graphical.target
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```
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GNOME Display Manager was active:
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```bash
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systemctl status gdm
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```
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Result:
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```text
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Active: active (running)
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```
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XRDP packages were installed:
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```bash
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rpm -qa | grep -Ei 'xrdp|xorgxrdp'
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```
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Result:
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```text
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xrdp-0.10.6.1-3.el8.x86_64
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xrdp-selinux-0.10.6.1-3.el8.x86_64
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xorgxrdp-0.10.5-1.el8.x86_64
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```
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---
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## 3. XRDP Root Login Failure
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### 3.1 Authentication Worked
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The XRDP session manager logs confirmed that root credentials were accepted:
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```text
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Access permitted for user: root
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Received sys login status for root : logged in
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login was successful - creating session
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```
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This ruled out:
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- Incorrect root password
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- PAM authentication failure
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- XRDP access control failure
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### 3.2 Xorg Started Successfully
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XRDP also successfully created an Xorg session:
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```text
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Starting X server on display 10
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X server :10 is working
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session is available on display 10 for user root
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```
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The RDP client connected to the Xorg session:
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```text
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lib_mod_log_peer: xrdp_pid=... connected to Xorg_pid=...
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```
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This ruled out:
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- Missing `xorgxrdp`
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- Xorg startup failure
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- XRDP-to-Xorg connection failure
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### 3.3 Window Manager Exited Immediately
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The critical log entries were:
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```text
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Window manager finished normally in 1 secs
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Window manager exited quickly
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This could indicate a window manager config problem
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Session on display has finished
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```
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This showed that the RDP connection itself was functional, but the GNOME/window-manager process terminated immediately.
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---
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## 4. Root Cause of the Root XRDP Session Failure
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XRDP debug logging showed:
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```text
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The user home directory window manager configuration is enabled but window manager program does not exist: /root/startwm.sh
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Using the default window manager on display 10: /usr/libexec/xrdp/startwm-bash.sh
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```
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The root cause was therefore the missing root-specific XRDP startup script:
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```text
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/root/startwm.sh
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```
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XRDP fell back to:
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```text
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/usr/libexec/xrdp/startwm-bash.sh
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```
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The fallback script did not correctly initialize a persistent GNOME desktop for the root XRDP session.
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---
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## 5. Initial Remediation for Root XRDP
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A root-specific XRDP startup script was created to explicitly start the GNOME session.
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Example initial configuration:
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```bash
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#!/bin/bash
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export XDG_SESSION_TYPE=x11
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export GDK_BACKEND=x11
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exec /usr/bin/gnome-session
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```
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Permissions and SELinux context were applied:
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```bash
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chmod 700 /root/startwm.sh
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restorecon -v /root/startwm.sh
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```
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XRDP services were restarted:
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```bash
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systemctl restart xrdp-sesman xrdp
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```
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After this change, the root user was able to log in to the graphical XRDP desktop.
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---
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## 6. GNOME Terminal Failure After Root Desktop Login
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After the desktop became functional, GNOME Terminal still did not open.
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A working `xterm` session was used for troubleshooting.
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The XRDP graphical environment contained a valid X11 display similar to:
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```text
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DISPLAY=:10.0
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```
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The system locale was also verified as UTF-8:
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```text
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LANG=en_US.UTF-8
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LC_CTYPE=en_US.UTF-8
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```
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GNOME Terminal was then tested through its user service.
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### 6.1 GNOME Terminal Service Failure
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The service status showed:
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```text
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gnome-terminal-server.service - GNOME Terminal Server
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Active: failed
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```
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The service exited with:
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```text
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status=10
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```
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The system journal provided the key failure:
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```text
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Unable to init server: Could not connect: Connection refused
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Failed to parse arguments: Cannot open display:
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```
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This confirmed that `gnome-terminal-server` could not connect to the XRDP X display.
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---
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## 7. D-Bus and systemd User Environment Investigation
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The root user runtime directory was present:
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```bash
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ls -l /run/user/0/bus
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```
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Result:
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```text
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srw-rw-rw- 1 root root ... /run/user/0/bus
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```
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The root systemd user manager was also running:
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```bash
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systemctl --user status
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```
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Result:
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```text
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State: running
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```
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However, the systemd user environment initially contained:
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```text
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LANG=en_US.UTF-8
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XDG_RUNTIME_DIR=/run/user/0
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```
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but did not contain:
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```text
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DISPLAY=:10.0
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XAUTHORITY=/root/.Xauthority
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```
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This was significant because `gnome-terminal-server` is activated through the root user's D-Bus/systemd user environment.
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The GNOME session and systemd user services were therefore operating with inconsistent session information.
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---
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## 8. D-Bus Session Conflict
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An earlier XRDP startup configuration used:
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```bash
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dbus-run-session /usr/bin/gnome-session
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```
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This created a separate temporary D-Bus session with an address similar to:
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```text
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unix:abstract=/tmp/dbus-...
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```
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At the same time, the root systemd user manager used the standard user bus:
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```text
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unix:path=/run/user/0/bus
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```
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The resulting architecture was effectively:
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```text
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XRDP / GNOME session
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+-- temporary dbus-run-session bus
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systemd --user
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+-- /run/user/0/bus
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```
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GNOME Terminal is implemented through `gnome-terminal-server`, which relies on the user's D-Bus/systemd activation environment.
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Because the two environments were not synchronized, the terminal server did not know which X11 display to use.
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---
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## 9. Final Root Cause
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The final root cause was a combination of:
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1. Missing `/root/startwm.sh`, causing XRDP to use an unsuitable default window-manager startup path.
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2. A D-Bus/systemd user-session environment that did not contain the XRDP X11 session variables.
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3. Use of `dbus-run-session`, which created a second temporary D-Bus session instead of using the standard root user bus.
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4. `gnome-terminal-server` being started without a valid XRDP `DISPLAY` and `XAUTHORITY`.
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The failure path was:
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```text
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XRDP authentication succeeds
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v
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Xorg starts successfully
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v
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GNOME desktop starts
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v
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systemd --user / D-Bus does not know XRDP DISPLAY
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v
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gnome-terminal-server cannot connect to Xorg
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v
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GNOME Terminal fails to open
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```
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---
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## 10. Final Working Configuration
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The final solution was to use the standard root user D-Bus and propagate the XRDP X11 session variables into the D-Bus/systemd activation environment.
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Final `/root/startwm.sh`:
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```bash
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#!/bin/bash
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export XDG_SESSION_TYPE=x11
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export GDK_BACKEND=x11
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export XDG_RUNTIME_DIR=/run/user/0
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export DBUS_SESSION_BUS_ADDRESS=unix:path=/run/user/0/bus
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export LANG=en_US.UTF-8
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export LC_CTYPE=en_US.UTF-8
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unset LC_ALL
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export XAUTHORITY=/root/.Xauthority
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dbus-update-activation-environment --systemd DISPLAY XAUTHORITY XDG_RUNTIME_DIR LANG LC_CTYPE
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exec /usr/bin/gnome-session
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```
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Permissions:
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```bash
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chmod 700 /root/startwm.sh
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restorecon -v /root/startwm.sh
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```
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XRDP services were restarted:
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```bash
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systemctl restart xrdp-sesman xrdp
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```
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---
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## 11. Validation
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After applying the final configuration:
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- Root authentication through XRDP succeeded.
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- The XRDP Xorg display started successfully.
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- GNOME desktop loaded successfully.
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- The root systemd user environment received the XRDP display information.
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- GNOME Terminal opened successfully.
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- `gnome-terminal-server` was able to connect to the active XRDP X11 display.
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- Normal XRDP desktop functionality was restored.
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Useful validation commands:
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```bash
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echo "$DISPLAY"
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echo "$DBUS_SESSION_BUS_ADDRESS"
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echo "$XAUTHORITY"
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echo "$XDG_RUNTIME_DIR"
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```
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Expected values are similar to:
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```text
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DISPLAY=:10.0
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DBUS_SESSION_BUS_ADDRESS=unix:path=/run/user/0/bus
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XAUTHORITY=/root/.Xauthority
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XDG_RUNTIME_DIR=/run/user/0
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```
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Check the user activation environment:
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```bash
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systemctl --user show-environment | grep -E '^(DISPLAY|XAUTHORITY|XDG_RUNTIME_DIR|LANG|LC_CTYPE)='
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```
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---
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## 12. Services and Components Involved
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| Component | Purpose | Status During Incident |
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| SSH | Remote command-line administration | Working |
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| GDM | GNOME Display Manager | Working |
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| XRDP | RDP protocol server | Working |
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| xrdp-sesman | XRDP session manager | Working |
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| xorgxrdp | Xorg backend for XRDP | Working |
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| Xorg | Graphical display server | Working |
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| GNOME Session | Graphical desktop environment | Initially failed for root |
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| D-Bus | IPC/session activation | Misaligned session environment |
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| systemd --user | Per-user service manager | Running but missing XRDP display variables |
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| gnome-terminal-server | GNOME Terminal backend | Failed to connect to X display |
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| xterm | Basic X11 terminal | Working |
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---
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## 13. Important Log Indicators
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### Successful authentication
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```text
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Access permitted for user: root
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Received sys login status for root : logged in
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```
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### Successful Xorg startup
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```text
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Starting X server on display 10
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X server :10 is working
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```
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### Initial desktop failure
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```text
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Window manager exited quickly
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This could indicate a window manager config problem
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```
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### Missing user startup script
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```text
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The user home directory window manager configuration is enabled
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but window manager program does not exist: /root/startwm.sh
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```
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### GNOME Terminal failure
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```text
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gnome-terminal-server.service: Main process exited
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status=10
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```
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### Actual terminal-server error
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```text
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Unable to init server: Could not connect: Connection refused
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Failed to parse arguments: Cannot open display:
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```
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---
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## 14. Troubleshooting Commands Used
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### XRDP status
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```bash
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systemctl status xrdp
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systemctl status xrdp-sesman
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```
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### XRDP packages
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```bash
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rpm -qa | grep -Ei 'xrdp|xorgxrdp'
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```
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### Graphical target
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```bash
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systemctl get-default
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```
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### GNOME Display Manager
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```bash
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systemctl status gdm
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```
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### XRDP logs
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```bash
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tail -300 /var/log/xrdp.log
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tail -300 /var/log/xrdp-sesman.log
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```
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### Xorg XRDP logs
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```bash
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ls -ltr /root/.xorgxrdp*
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```
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### Channel logs
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```bash
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find /root /var/log -type f -name 'xrdp-chansrv*.log'
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```
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### GNOME Terminal status
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```bash
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systemctl --user status gnome-terminal-server.service
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```
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### GNOME Terminal service exit information
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```bash
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systemctl --user show gnome-terminal-server.service -p Result -p ExecMainCode -p ExecMainStatus -p ExecStart
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```
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### System journal
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```bash
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journalctl -b --no-pager | grep -Ei 'gnome-terminal|terminal-server'
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```
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### Root user D-Bus
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```bash
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ls -l /run/user/0/bus
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```
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### Root systemd user environment
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```bash
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systemctl --user show-environment
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```
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---
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## 15. Preventive Actions
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1. Keep a documented root-specific XRDP startup configuration if root graphical access is operationally required.
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2. Avoid creating an unnecessary second D-Bus session with `dbus-run-session` when a systemd user bus is already available.
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3. Ensure XRDP session variables are propagated to the systemd/D-Bus activation environment:
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- `DISPLAY`
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- `XAUTHORITY`
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- `XDG_RUNTIME_DIR`
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- `LANG`
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- `LC_CTYPE`
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4. Keep XRDP debug logging available for troubleshooting, but reduce verbosity after resolution.
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5. Monitor `/var/log/xrdp.log` and `/var/log/xrdp-sesman.log` for session startup failures.
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6. Back up `/etc/xrdp/` and `/root/startwm.sh` after confirming the working configuration.
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7. Prefer standard administrative users with privilege escalation where possible, because graphical root sessions are atypical and can create application compatibility issues.
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---
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## 16. Backup Recommendation
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Back up the working XRDP configuration:
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```bash
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mkdir -p /root/xrdp-config-backup
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cp -a /etc/xrdp /root/xrdp-config-backup/
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cp -a /root/startwm.sh /root/xrdp-config-backup/
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```
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Optional archive:
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```bash
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tar -czf /root/xrdp-working-config-$(date +%F).tar.gz /etc/xrdp /root/startwm.sh
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```
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---
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## 17. Incident Resolution Status
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|
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**Resolved**
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Final service state:
|
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```text
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SSH Working
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XRDP Working
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Root XRDP authentication Working
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Xorg XRDP session Working
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GNOME desktop Working
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D-Bus user session Working
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systemd --user Working
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GNOME Terminal Working
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|
```
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The final resolution was achieved by aligning the XRDP X11 graphical session with the root user's standard D-Bus and systemd user-service environment.
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