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SSH connection with authentication using public key cryptography 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.Remote connection via SSHSSH 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 Edit SSH service configuration fileModify the configuration file to change the SSH service settings.The SSH service configuration file is "/etc/ssh/sshd_config".2.Firewall (firewalld) settingsThe firewall is set to firewalld as default and is enabled during OS installation.4.NTP ServerBuild an NTP server to synchronize the server time with Japan Standard Time

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 operating modesEnforcing : 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 disabled2.System ModernizationPackage 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.

Rocky Linux9.3The Rocky Release Engineering team announced the latest version of Rocky Linux 9.0 on July 14, 2022.Rocky Linux is a Linux distribution compatible with Red Hat Enterprise Linux; Rocky Linux 9 is a compatible release with RHEL 9 released in May and will be supported until the end of May 2032.This time we will install Rocky Linux 9.3, released NOVEMBER 20, 2023.

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

1. Logwatch①Install# dnf install logwatch②Edit configuration file2.Introduce disk usage check script2.1 Script Creation# cd /var/www/system# vi disk_capacity_check.sh

SNORT3 Snort 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 various attacks such as “buffer overflows,” “stealth port scans,” “CGI attacks,” “SMB probes,” “OS fingerprinting attempts,” “semantic URL attacks,” and “server message block probes. The system can be used to detect a variety of attacks, such as

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 RepositoryTripwire1.Installation# dnf install -y tripwireChkrootkit①Download and install chkrootkit

MySQL8 Install＃ dnf -y install mysql-servercharset.cnf   Create a new one with the fWordPress Install1. Create database for Word PressAs an example, assume database [wp_db] database user [wp_user] password [?Ww123456]

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.

clamav (anti-virus software] Install1.Clam AntiVirus install# dnf -y install clamav clamd clamav-update2.Clam AntiVirus  Configuration File EditMail Server Install1. Postfix1.1 InstallInstall Postfix and build an SMTP serverMail : Postfix + Clamav + clamav-milter+SpamAssassin1.Real-time scanning of e-mails①clamav-milter InstallVirus checks are performed on the mail server side using Clam AntiVirus.The mail server and Clam AntiVirus are linked using clamav-milter.

1.Apache2 Install , Virtual Host Configuration1.1 Apache2 install①httpd install# dnf -y install httpd1.3 Virtual Host SettingsAssign and configure the domain name [rocky.korodes.com] to the document root [/var/www/html/rocky.korodes.com] directory for virtual host operation2. Use of CGI Scripts①CGI availability check3. PHP installation and configuration1.PHP8 Install4. 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 informa

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

SSH connection with authentication using public key cryptography 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.Remote connection via SSHSSH 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 Edit SSH service configuration fileModify the configuration file to change the SSH service settings.The SSH service configuration file is "/etc/ssh/sshd_config".2.Firewall (firewalld) settingsThe firewall is set to firewalld as default and is enabled during OS installation.4.NTP ServerBuild an NTP server to synchronize the server time with Japan Standard Time