System-config-firewall-tui does not startup on CentOS – Failed to connect to socket system_bus_socket [Solved]

Question: Hi, I’m a newbie using CentOS 6.6. I tried to configure Firewall settings via setup > Firewall Configuration. Unfortunately, the tool didn’t show up firewall configuration screen and when I exit the utility, I saw the below error. The same error was obtained when I run ‘system-config-firewall-tui‘ command as well. I did spend some time in searching this issue across various Linux forums – where few users said that the issue is common when ‘setup‘ command was run after ‘yum update‘. They also suggested that the only solution is to reboot the machine. But I’m not sure if that’s the right way of doing it. Do you have any suggestions?

– Abhi

# system-config-firewall-tui
 Traceback (most recent call last):
 File "/usr/bin/system-config-firewall-tui", line 29, in <module>
 import fw_tui
 File "/usr/share/system-config-firewall/fw_tui.py", line 34, in <module>
 import fw_nm
 File "/usr/share/system-config-firewall/fw_nm.py", line 30, in <module>
 bus = dbus.SystemBus()
 File "/usr/lib/python2.6/site-packages/dbus/_dbus.py", line 202, in __new__
 private=private)
 File "/usr/lib/python2.6/site-packages/dbus/_dbus.py", line 108, in __new__
 bus = BusConnection.__new__(subclass, bus_type, mainloop=mainloop)
 File "/usr/lib/python2.6/site-packages/dbus/bus.py", line 125, in __new__
 bus = cls._new_for_bus(address_or_type, mainloop=mainloop)
 dbus.exceptions.DBusException: org.freedesktop.DBus.Error.FileNotFound: Failed to connect to socket /var/run/dbus/system_bus_socket: No such file or directory

Solution:

Abhi, rebooting the system helps sometime (leave out the debate right or wrong). Instead you should try restarting the ‘messagebus‘ service (start if it’s not running already) and see if the error goes away (also it makes sense because the error is related to the bus and tries to connect to a listening socket as well).

What is messagebus daemon?
Message bus daemon is a library is enables one application or a program to exchange message with another. It's basically enables one-to-one communication between programs. It's also called as D-BUS message bus daemon.

# service messagebus start
Starting system message bus: [ OK ]

If you do not find the messagebus service installed, you can install using the below command or refer this tutorial:

# yum install dbus

Once you confirm that the ‘messagebus‘ service is running. Try ‘setup‘ or ‘system-config-firewall-tui‘ command.

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