2023

SSH connection with authentication using public key Creation 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_ed25519.pub will be created in /home/(user name)/.ssh/. On the way, enter the password for the key.

1.FTP Server1.1vsftpd Install# dnf -y install vsftpd1.2vsftpd configurationSave the unedited vsftpd.conf with .bak# cp /etc/vsftpd/vsftpd.conf /home/huong/vsftpd.conf.bak2. vsftpd SSL/TLSConfigure Vsftpd to use SSL/TLS2.1 Create self-signed certificatesThis work is not required if you are using a trusted, legitimate certificate such as Let's Encryp3. 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 Edit

1.Apache2 Install , Virtual Host Configuration1.1 Apache2 install2. Use of CGI Scripts①CGI availability check3. PHP installation and configuration4. Digest authentication with Apache2Since 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 information, so there is almost no risk of information leakage.

Clamav(anti-virus)1.Clam AntiVirus install# dnf -y install clamav clamd clamav-updateMail Server Installation1. Postfix1.1 InstallInstall Postfix and build an SMTP serverMail server : Postfix + Clamav + Amavisd+SpamAssassin1.Real-time scanning of e-mails①Install Amavisd and Clamav Server

1.Obtain SSL Certificate ( Let's Encrypt )Install the latest open ssl# dnf install openssl-devel1.1 Certificate Installation# dnf -y install certbot# certbot certonly --webroot -w /var/www/html/[FQDN] -d [FQDN]# Registration of e-mail address and agreement to terms of use are required for the first time only.# Specify an email address to receive2. Converting Apache to httpsInstall the following# dnf -y install mod_ssl2.1 Edit ssl.conf file3. 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-serverCreate a new charset.cnf 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.

1. Logwatch①Install# dnf install logwatch②Editing Configuration Files2.Automatic DNS update scriptWhenever the global IP changes, which happens when the network is disconnected or the router is disconnected and rebooted, we need to access Dynamic DNS to inform the user that the global IP has changed. We will install a script that will do this automatically.This time, we assume that you will use Value Domain as your DNS service.3.Disk Usage Check Script3.1 script# cd /var/www/system# vi disk_capacity_check.sh

1.Website data backup1-1. Backup under /var/www/html①Creating backup script files# cd /var/www/system# vi backup_html.sh2.MySQL database backup①Creating backup script files# cd /var/www/system3.Restore backup files under html① Store HTML backup files in "/ (root)" directory4.Restoring Mysql Backup Files①Save the backup file to any directory（In the example, the directory is "/var/www/backup/db_bak".）Unzip data

What is Icinga2?It is an open source software for system monitoring, derived and developed from a monitoring software called Nagios.In this article, we will install the Icinga2 monitoring application on OracleLinux8.x with RHEL8.The same can be done on Rocky Linux8.x and AlmaLinux8.x.However, please note that some information related to PowerTools is different from the information on this page.1.Prerequisite.The requirement for installing Icinga2 is that you must have LAMP installed. PHP 7.3 or later version is also required.In this case, it is assumed that the following have been builtMySQL 　　Ver 8.0.32PHP　　　　7.4.33Httpd　　　Apache/2.4.37 SELINUX   permissive

 SuricataSURICATA 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 preparation①Activate the EPEL RepositorySNORTSnort is an open source network intrusion detection system that can perform 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 such as buffer overflows, stealth port scans, CGI attacks, SMB probes, OS fingerprinting attempts, semantic URL attacks, and server message block probes. detection.

Tripwire1.Download and installation# cd /usr/local/src# wget https://rpmfind.net/linux/epel/9/Everything/x86_64/Packages/t/tripwire-2.4.3.7-13.el9.x86_64.rpm# rpm -Uvh tripwire-2.4.3.7-13.el9.x86_64.rpmChkrootkit①Download and install chkrootkit# cd /usr/local/src# wget https://launchpad.net/chkrootkit/main/0.55/+download/chkrootkit-0.55.tar.gz# tar xvf chkrootkit-0.55.tar.gzLogwatch①Install# dnf install logwatchIntroduce disk usage check script1. Script Creation# cd /var/www/system# vi disk_capacity_check.sh

1.Website data backup1-1.Backup under /var/www/html①Create backup script file2.MySQL database backup①Create backup script file# cd /var/www/system# vi db_my_backup.sh3.Restore backup files under html① Store HTML backup files in "/ (root)" directory# cd /var/www/backup/html_bak# cp html_back_20220610.tar.gz / ←Specify the backup file with the latest date4.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# cd /var/www/backup/db_bak