NetworkManager is normally good for GUI users who may not be good with manually confguring devices, but if you are using things like bridging and bonding, it will often break things.
How To Disable NetworkManager
systemctl disable NetworkManager
Now that it's disabled you will need to stop NetworkManager. NetworkManager will still be running until you reboot next or manually stop it.
How To Stop NetworkManager
systemctl stop........
Yes you have that right, the network service in RHEL8 / CentOS 8 / Rocky Linux / Alma Linux no longer exists. So there is no more systemctl restart network
You can restart NetworkManager but it doesn't have the same effect or ifup/ifdown on all interfaces.
Generally if NetworkManager is installed you will want to restart it or it won't apply the settings from ifcfg.
systemctl restart NetworkManager
To repl........
This is not the normal "black screen"issue and I was shocked to eventually find out why. The normal advice of reconfiguring Xorg didn't work. Even booting into "Recovery Mode" did not help.
Here is the short end of the stick that fixed it:
sudo apt-get install mdm mate-desktop-environment
Yes you got it right, mdm and the mate-desktop-environment / gnome were somehow uninstalled. This must be whe........
The Scenario
You have dual NICs and you disable NIC1 which uses 192.168.1.1 as its gateway. With NIC2 you enable it/connect it to another network which also has the gateway 192.168.1.1
Everything will work fine at this point.
When switching back to NIC1 even with NIC2 disabled and even unplugged, the OS basically can't pick up the new/updated ARP entry of the old device for 192.168.1.1 and perhaps thinks it is a security risk or spoof of some sorts and blocks i........
pxe-32 tftp open timeout
The solution was to enable tftp in xinetd with "chkconfig tftp on".
See the troubleshooting below:
chkconfig --list
NetworkManager 0:off 1:off 2:off 3:off 4:off 5:off 6:off
acpid 0:off&n........
I've never understood how to enable and disable services for different run levels in Debian based distros, it's just weird, annoying and doesn't make sense. I much prefer chkconfig from RHEL.
Just install the package called 'rcconf' and be done with it. rcconf makes things easy for you.
apt-get install rcconf
Reading package lists... Done
Building dependency tree
Reading state information... Done........
Apr 30 17:07:07 localhost kernel: [12265558.582378] r8169: eth0: link up
Apr 30 17:07:07 localhost NetworkManager: (eth0): carrier now ON (device state 1)
Apr 30 17:07:08 localhost kernel: [12265559.237961] r8169: eth0: link down
Apr 30 17:07:08 localhost NetworkManager: (eth0): carrier now OFF (device state 1)
Apr 30 17:07:11 localhost NetworkManager: (eth0): carrier now ON (device state 1)
Apr........