3-minute fever 三分鐘熱度

This should be the third last topic that I'd like to share related to my RHCE course, but my brain just hang there without any progress. So I proceed with SELinux and firewall first. I am still trying to understand the networking terms, teaming and bridge are 2 new words that I learned from RH Admin III course. Actually, I still don't quite understand what is the usage for these. When I setup VirtualBox for this series of sharings, I started to understand more for bridge... Anyway, let me stay focus on the topic (how-to). The Network Manager commands (nmcli) are rather easy to use, if you know what you are trying to do. Network teaming I did some hacks to make 2 available interfaces, enp0s8 and enp0s10. Next, create a team master. This team master will configured to activebackup setting, i.e. one port/link is used while other reserved as backup. Now create the team slaves (team ports). Use teamdctl to see the status of the teaming. This is provided in teamd pac...

By default, firewalld is ready installed when you setup your machine. So, nothing extra needs to be install in order to use this. Basically, there are a few default zones predefined and by default, the public zone will be set as the default zone. I got this from man firewalld. List of predefined zones, and the default zone. Basic firewall command is to allow external to access local machine services or port. To list current firewall rules. To allow a service or port. To remove the service or port from firewall rule, simply replace the add to remove . Note that, this is just a temporary allowing the service and port. After the firewalld service restarted, these rules will be gone. To make it permanent, run again the commands with additional --permanent option. Another way is, run the command with --permanent option first, then run firewall-cmd --reload . For a more complicated firewall rule setting, which uses rich language. You may set to drop or reject or accept...

There are 2 ways, one is fully setup in Oracle VirtualBox, the other way is setups in both host and VirtualBox. These methods might not limited for access to the web server in virtual machine, but probably also to access samba server in virtual machine and etc. I haven't tested with other services though. To keep it simple, we'll use a simple httpd service in the VirtualBox machine. Requisites 1. httpd is running in virtual machine. 2. firewall rule in virtual machine allow the access to the http service 3. a test web page is created for the httpd run. To test the web service is working fine in the virtual machine, run the following in virtual machine. OK, let's get started. Power off your virtual machine. Launch the Settings of your virtual machine in VirtualBox Manager. Bind the virtual machine with the host. Set as below: The Host-only Adapter allows the access from your host machine to this virtual machine. With only this setting, your host machine i...