Initial Configurations for Newly Installed CentOS 8 Server

By | August 28, 2020

Network Configuration Settings

During the installation of CentOS 8, we already assigned the static IP address configuration. The following steps are just in case you want to modify/change to any other IP addresses or DNS server IP.

NOTE: Replace the interface name to your own, it’s difference for any other system. In my case, I use eth0.

1. Edit the network adapter configuration file

 2. Modify/change below network settings and save. 

3. Restart network service by bring down and bring up the network interface.
4. You also can use command line (CLI Commands) to configure network settings
  • Set manual for static setting:  #nmcli connection modify eth0 ipv4.method manual
  • Set IP address:  #nmcli connection modify eth0 ipv4.addresses 192.168.200.200/24
  • Set Default Gateway:  #nmcli connection modify eth0 ipv4.gateway 192.168.200.1
  • Set DNS Server IP:  #nmcli connection modify eth0 ipv4.dns 8.8.8.8
  • Restart interface:  #nmcli connection down eth0; nmcli connection up eth0
5. Show your network interface settings
6. Show your network interface status

Firewall Service

1. The firewall service is running by default, you can this service using following command.
2. If you want to stop the firewall service, use the following command

3. If you want to permanently disable the Firewall service, use the following command

4. Enable and Start the Firewall service

5. When Firewall service is running, the incoming traffic is blocked by default. If you want the incoming traffic for specific application, you need to modify/add firewall rule. Example below I will allow the incoming traffic for HTTP port 80.

SELinux

Security-Enhanced Linux is a Linux kernel security module that provides a mechanism for supporting access control security policies, including mandatory access controls.

1. To show SELinux status, use the following command. Enforcing mean SELinux is enabled
2. Sometimes, SELinux stop the access to your application hosting in your CentOS server and you may want to disable it. Change SELinux setting from Enforcing to disabled in this path /etc/selinux/config

3. Save and reboot your system to apply the change.

Managing CentOS 8 with Web Admin Console

1. CentOS 8 is by default installed with Cockpit Admin Console which allows you to manage your server via web browser. All you need to do is to enable the service like following:

2. Cockpit is listening on port 9090 which mean Cokpit service is now up.

3. Inbound traffic for Cockpit is allowed by default. If it is not, use the following command to allow it.

    You see the warning because cockpit already enabled and running on my server

4. Access to Web Admin Console via browser

5. You have now successfully login to your CentOS 8 server via web browser

In the next article, we will see the NTP Server and NTP Client, please refer to NTP Server and Client Configuration

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