2023

1.Disabling SELinuxFirst, 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 Operation ModeEnforcing : SELinux functionality is enabled and access control is enabledPermissive : SElinux will warn, but no access restrictions will be placeddisabled : Both SElinux function and access control are disabled

1.Setting up SSH remote connectionSSH is a service to connect to a server remotely, and is basically running right after the OS installation, but the default settings are somewhat insecure.In this section, we will configure the settings to change the default settings and increase the security of the ssh connection.1.1 Change the configuration file of SSH service.The configuration file for the SSH service is "/etc/ssh/sshd_config". Open the configuration file with vi editor

SSH connection with authentication using public key cryptographyCreation of public and private key pairsCreate 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.FTP Server1. 1 Vsftpd Install# dnf -y install vsftpd1.2 Configure VsftpdSave the unedited vsftpd.conf with .bak3. File server installation with SambaBuild a file server with access rights that requires user authentication with Samba.Installation Procedure①Create shared folders with access rights that require user authentication②Accessible group creation③Creation of users belonging to accessible groups④Configuration File Editing

Clamav (anti-virus software)Install1.Clamav install# dnf -y install clamav clamd clamav-update2.Clam AntiVirus  Configuration File EditMail Server Install1. Postfix1.1 InstallInstall Postfix and build an SMTP server2.Dovecot2.1 dovecot install# dnf -y install dovecot2.2 Edit dovecot.conf fileMail Server : Postfix + Clamav + Amavisd+SpamAssassin1.Real-time scanning of e-mails①Install Amavisd and Clamav Server

1.Obtain an SSL certificate ( Let's Encrypt )Install the latest open ssl# dnf install openssl-devel1.1 advance preparation1.Package management system Snappy installedSince 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 httpsInstall the following just in case# dnf -y install mod_ssl3. SSL/TLS (Let's Encrypt) settings on the mail server3.1 Obtaining a certificate for the mail serverObtain 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.

Mysql8 Install＃ dnf -y install mysql-servercharset.cnf   Create a new one with the following contentsWordPress Install1. Create database for Word PressAs an example, assume database [wp_db] database user [wp_user] password [?W123456]

Snort3 InstallSnort is an open source network intrusion detection system capable of performing real-time traffic analysis and packet logging on IP networks.It can perform "protocol analysis," "content search," and "matching," and can be used to detect a variety of attacks, including "buffer overflows," "stealth port scans," "CGI attacks," "SMB probes," "OS fingerprinting attempts," "semantic URL attacks," and "server message block probes.MiracleLinux8 does not have a Snort3 repository, so build, compile and install Snort3 from source code1. Advance preparation①Install required build tools and libraries

chkrootkit①Download and install chkrootkit# cd /usr/local/src# wget ftp://ftp.chkrootkit.org/pub/seg/pac/chkrootkit.tar.gz# tar xvf chkrootkit.tar.gz➁Create /root/bin directory and move chkrootkit command to that directory# mkdir -p /root/bin# mv chkrootkit-0.58b/chkrootkit /root/bin➂Check chkrootkit.Logwatch①Install # dnf install logwatch②Edit configuration file

1.Website data backup1-1.Backup under /var/www/html①Create backup script file# cd /var/www/system# vi backup_html.sh2.MySQL database backup①Create backup script file# cd /var/www/system# vi db_my_backup.sh3.Restore backup files under html①Store HTML backup files in "/ (root)" directory4.Restore Mysql backup file①Save the database backup file to any directory and（In the example, the directory is "/var/www/backup/db_bak".）Extracting data