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Almalinux9.3_en

Almalinux9.3_en

AlmaLinux9.3 ; OS Install

AlmaLinux 9.3 Install AlmaLinux OS is a project launched by CloudLinux in the US as an alternative to CentOS. Currently, the AlmaLinux OS Foundation is the development parent organization.Following the general availability of Red Hat Enterprise Linux 9.0, AlmaLinux 9.0 was released on May 26, 2022. Like Red Hat Enterprise Linux 9, AlmaLinux 9 utilizes the same package versions as the Linux 5.14 kernel, GCC 11, Python 3.9, and RHEL9. Cockpit web management interface, enhanced kernel live patching, improved container and cloud integration, OpenSSL 3, and other security improvements. This time we will install AlmaLinux 9.3 with a minor upgrade on Nov 11, 2023. 1.AlmaLinux 9.3 Download AlmaLinux 9.3 installation image can be downloaded from the following site https://almalinux.org
Almalinux9.3_en

AlmaLinux9.3 ; Various settings after installation

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 Update packages as soon as possible after OS installation. 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.
Almalinux9.3_en

AlmaLinux9.3 ; SSH、Firewalld、NTP Server

1. SSH remote connection 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. 2.How to set up a firewall (firewalld) In AlmaLinux, the firewall is set to firewalld by default and is enabled during OS installation. 2.1 How to use the "firewall-cmd" command to control "firewalld" 1)How to use the "firewall-cmd" command to control "firewalld" ①Check firewalld operation status 3.Remote connection from Windows Setup in Windows Start setting up a remote connection from Windows, using "Tera Term" as the terminal emulator. Start Tera Term, cancel the startup screen, and then select "New Connection" from "File" in the Tera Term menu.
Almalinux9.3_en

AlmaLinux9.3 ; SSH connection with public key

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_ed25519.pub will be created in /home/(user name)/.ssh/. On the way, enter the password for the key.
Almalinux9.3_en

AlmaLinux9.3 ; FTP Server , Samba File Server

1.FTP Server 1. 1 Vsftpd Install # dnf -y install vsftpd 1.2 Configure Vsftpd Save the unedited vsftpd.conf with .bak 3. File server installation with Samba Build a file server with access rights that requires user authentication with Samba. Installation Procedure ①Create shared folders with access rights that require user authentication ②Accessible group creation ③Creation of users belonging to accessible groups ④Configuration File Editing
Almalinux9.3_en

AlmaLinux9.3 ; WEB Server(Apache2) & Virtual Hosts

1.Apache2 Install , Virtual Host Configuration 1.1 Apache2 install ①httpd install # dnf -y install httpd 1.3 Virtual Host Settings Assign and configure the domain name [rocky.korodes.com] to the document root [/var/www/html/rocky.korodes.com] directory for virtual host operation 2. Use of CGI Scripts ①CGI availability check 3. PHP installation and configuration 1.PHP8 Install 4. Digest authentication with Apache2 Since Basic Authentication, a well-known authentication authorization method for http, sends authentication information in plain text, there is a risk of ID and password leakage if the packet is intercepted. On the other hand, Digest Authentication encrypts and transmits authentication informa
Almalinux9.3_en

AlmaLinux9.3 ; Anti-virus(Clamav) , Mail Server

clamav (anti-virus software] Install 1.Clam AntiVirus install # dnf -y install clamav clamd clamav-update 2.Clam AntiVirus  Configuration File Edit Mail Server Install 1. Postfix 1.1 Install Install Postfix and build an SMTP server Mail : Postfix + Clamav + clamav-milter+SpamAssassin 1.Real-time scanning of e-mails ①clamav-milter Install Virus checks are performed on the mail server side using Clam AntiVirus. The mail server and Clam AntiVirus are linked using clamav-milter.
Almalinux9.3_en

AlmaLinux9.3 ; SSL Certificate Acquisition( Let's Encrypt ) , Apache SSL , Mail SSL/TLS

1.Obtain an SSL certificate ( Let's Encrypt ) Install the latest open ssl # dnf install openssl-devel 1.1 advance preparation 1.Package management system Snappy installed Since the SSL certificate issuing tool "certbot" of Let's Encrypt is recommended to be installed using "snap" after 2021, install Snapd first.(Can also be installed the traditional way with dnf or yum) 2. Converting Apache to https Install the following just in case # dnf -y install mod_ssl 3. SSL/TLS (Let's Encrypt) settings on the mail server 3.1 Obtaining a certificate for the mail server Obtain a certificate for the mail server, but it cannot be obtained in the same way as above, so the following with the "--standalone" option fails.
Almalinux9.3_en

AlmaLinux9.3 ; MySQL8 , WordPress Install

MySQL8 Install # dnf -y install mysql-server charset.cnf   Create a new one with the f WordPress Install 1. Create database for Word Press As an example, assume database [wp_db] database user [wp_user] password [?Ww123456]
Almalinux9.3_en

AlmaLinux9.3 ; Suricata , Tripwire , Chkrootkit

Suricata SURICATA IDS/IPS is an open source IDS that monitors communications on the network and detects suspicious traffic. The basic mechanism is signature-based, so it can detect predefined unauthorized communications. Suricata is also characterized by its ability to provide protection as well as detection. 1.advance preparation ①Activate the EPEL Repository Tripwire 1.Installation # dnf install -y tripwire Chkrootkit ①Download and install chkrootkit
Almalinux9.3_en

AlmaLinux9.3 ; Logwatch , Disk Usage Check Script

1. Logwatch ①Install # dnf install logwatch ②Edit configuration file 2.Introduce disk usage check script 2.1 Script Creation # cd /var/www/system # vi disk_capacity_check.sh
Almalinux9.3_en

AlmaLinux9.3 ; System Backup and Restore

1.Website data backup 1-1.Backup under /var/www/html ①Create backup script file # cd /var/www/system # vi backup_html.sh 2.MySQL database backup ①Create backup script file # cd /var/www/system # vi db_my_backup.sh 3.Restore backup files under html ①Store HTML backup files in "/ (root)" directory 4.Restore Mysql backup file ①Save the database backup file to any directory and (In the example, the directory is "/var/www/backup/db_bak".)Extracting data