2023

OracleLinux9.2Oracle Linux provides a 100% application binary compatible alternative to Red Hat Enterprise Linux and CentOS Linux for both hybrid and multi-cloud environments.Since 2006, Oracle Linux has been completely free to download and use. Source code, binaries and updates are provided free of charge. It is freely redistributable. Free for use in production environments.今回は、最新のOracle Linux9.2(2023年5月リリース)で進めていきます。This time, we will proceed with the latest Oracle Linux 9.1.(May 2023 Release)１．Oracle Linux9.2 DownloadOracle Linux 9.2 installation image (OracleLinux-R9-U2-x86_64-dvd.iso ) can be downloaded from the following sitehttps://www.oracle.com/linux/

1.Install bash completion extension package# dnf -y install bash-completion# reboot2.Disabling SELinuxFirst, disable selinux.　selinux is a feature that improves auditing and security in Linux, but when enabled, it can limit the behavior of services and the contents of the configuration considerably.Therefore, it is basically a case of invalidation 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 disabled

1.Setting up a 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.2.Firewall (Firewalld) settingsIn Oracle, the firewall is firewalld configured by default and enabled during OS installation.To briefly explain "firewalld," when setting communication control policies, communication permission/blocking rules are applied to predefined zones, and these zones are then assigned to each NIC (network adapter).

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

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.