Debian12.1_en Debian12 ; NTP ,FTP Server Installation
1. Install NTP server
2. Install FTP Server
2.1 Install Vsftpd
2023-06
Debian12.1_en 
Debian12.1_en Debian12 ; SSH connection using public key cryptography
Create public and private key pairs
Create a public/private key pair for a user connecting to a Linux server using OpenSSH.
Use ssh-keygen to create the key pair.
This time, we will create a key set using the RSA cipher used in the SSH protocol Version 2.
The creation of a public/private key pair is performed with remote login user privileges (e.g., huong).
If you do not specify the destination and file name, id_rsa and id_rsa.pub will be created in /home/huong/.ssh/. On the way, enter the password for the key.
Debian12.1_en Debian12 ; SSH , Firewall Setting
1. SSH Service Security Settings
The SSH service allows the root user to log in by default, and since the root user already knows the user name and can log in to the server with administrative privileges once the password is known, we will deny this setting.
1.1 Creating a General User
If you have created a general user when installing Debian, this procedure is not necessary.
If the only user created on the server is root, remote login via SSH will not be possible, so if a user has not been created during OS installation, a user must be created in advance.
Users can be created with the "useradd" command. The "-m" option creates a home directory and the "-p" option specifies the password.
For example, to set "debianuser" as the user account name and "123456" as the password, execute the following
Debian12.1_en Debian12 ; Initialization
1.Installing and configuring the vim editor
Debian has "nano" as the default editor. nano is somewhat difficult to use, and there are few environments where it is used, so we will introduce the procedure for changing the editor to "vim".。
1.1 Check vim package
Debian has vim installed by default, but it is a package called "vim-tiny", which is a less functional version. Let's check the installed vim package.
Debian uses the "dpkg" command to check packages. The "-l" option displays a list of packages.
Since the "dpkg" command as is will show all packages installed on the system, we will use the "grep" command to extract only those packages that contain the string "vim". Execute as follows
OpenSUSE15.5_en OpenSUSE15.5 ; Snort2 Install
1.SNORT2
Snort is a network-based IDS (Intrusion Detection System). It captures packets flowing over a network and detects suspicious packets.
The source file is used directly from https://snort.org/.
1.1 Advance preparation
Install required libraries
OpenSUSE15.5_en OpenSUSE15.5 ; Firewall , SSH、NTP Server
1. Setting up remote connection by SSH
SSH is a service for connecting remotely to a server and is basically running immediately after the OS is installed, but the default settings are somewhat insecure.
Here we will configure the default settings to increase the security of ssh connections.
1.1 SSH service configuration file changes
Modify the configuration file to change the SSH service settings.
The SSH service configuration file is "/etc/ssh/sshd_config".
OpenSUSE15.5_en OpenSUSE15.5 ; SSH connection with public key
Create a private key for the client and a public key for the server to allow login with key pair authentication
1.key pair creation
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 creation destination and file name, id_ecdsa and id_ecdsa.pub will be created in /home/(user name)/.ssh/.
On the way, also enter the password for the key.
OpenSUSE15.5_en OpenSUSE15.5 ; MariaDB , WordPress Install
1. MariaDB Install
Update the server package
1.2 phpMyAdmin Install
Installed phpMyAdmin and configured it to operate MariaDB via web browser
2. Wordpress Install
2.1 Required library installation