2022-11

1.Disabling SELinux First, disable selinux. selinux is a feature that improves auditing and security in Linux, but when enabled, it places considerable restrictions on the behavior of services and on what can be configured. Therefore, it is basically disabled in many cases. SELinux operating modes Enforcing : SELinux functionality is enabled and access control is enabled Permissive : SElinux will warn, but no access restrictions will be placed disabled : Both SElinux function and access control are disabled 2.System Modernization Package updates are performed as soon as possible immediately after OS installation. However, when a dnf update is performed, a kernel update is also performed at the same time. A kernel update may require rebooting the system or stopping services, or worse, a kernel panic may occur and the system may not boot. It is wiser to exclude the kernel from the update. The kernel can be excluded from updates by running dnf -y update with "--exclude=kernel*" after it.

SSH connection with authentication using public key cryptography Creation of public and private key pairs Create a public/private key pair for a user connecting to the Linux server using OpenSSH. Use ssh-keygen to create key pairs. Creation of public/private key pairs is performed with remote login user privileges。 If you do not specify the destination and file name, id_ed25519 and id_eed25519.pub will be created in /home/(user name)/.ssh/. On the way, enter the password for the key.

1. Logwatch ①Install # dnf install logwatch ②Edit configuration file 2. DiCE Whenever the global IP changes, which happens when the network is disconnected or the router is disconnected and rebooted, the dynamic DNS must be accessed to inform the user that the global IP has changed. DiCE does this automatically! 3.Introduce disk usage check script 3.1 Script Creation # cd /var/www/system # vi disk_capacity_check.sh