Contents
1. Disable 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.
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# getenforce ← Check SELinux functionality Enforcing ← SELinux is effective # setenforce 0 ← Disable SELinux functionality # getenforce ← Reconfirmation of SELinux functionality Permissive ← SELinux functionality is disabled. |
As it is, seinux will return to be enabled once the server is restarted, so to permanently disable selinux, modify the /etc/sysconfig/selinux file.
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# vi /etc/sysconfig/selinux |
Change "SELINUX=enforcing" to "SELINUX=disabled"
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# This file controls the state of SELinux on the system. # SELINUX= can take one of these three values: # enforcing - SELinux security policy is enforced. # permissive - SELinux prints warnings instead of enforcing. # disabled - No SELinux policy is loaded. #SELINUX=enforcing SELINUX=disabled # SELINUXTYPE= can take one of these three values: # targeted - Targeted processes are protected, # minimum - Modification of targeted policy. Only selected processes are pro tected. # mls - Multi Level Security protection. SELINUXTYPE=targeted |
2. System Modernization
Package 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.
By running dnf -y update with "--exclude=kernel*" after
kernel*" after "update" to exclude the kernel from updates.
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# dnf -y update --exclude=kernel* |
3.Services to be stopped due to security measures
Stop the following services that you deem unnecessary.
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# systemctl stop atd.service # systemctl disable atd.service # systemctl stop kdump.service # systemctl disable kdump.service # systemctl stop lvm2-monitor.service # systemctl disable lvm2-monitor.service # systemctl stop mdmonitor.service # systemctl disable mdmonitor.service # systemctl stop smartd.service # systemctl disable smartd.service # systemctl stop tuned.service # systemctl disable tuned.service # systemctl stop dm-event.socket # systemctl disable dm-event.socket |
4.Adding Repositories
4.1 Add EPEL repository
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# dnf -y install epel-release # vi /etc/yum.repos.d/epel.repo |
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[epel] name=Extra Packages for Enterprise Linux $releasever - $basearch # It is much more secure to use the metalink, but if you wish to use a local mirror # place its address here. #baseurl=https://download.example/pub/epel/$releasever/Everything/$basearch metalink=https://mirrors.fedoraproject.org/metalink?repo=epel-$releasever&arch=$basearch&infra=$infra&content=$contentdir enabled=1 ← Repository enabled (0 : Repository disabled) priority=10 ← Specify priority in the range of 1~99 gpgcheck=1 countme=1 gpgkey=file:///etc/pki/rpm-gpg/RPM-GPG-KEY-EPEL-8 [epel-debuginfo] name=Extra Packages for Enterprise Linux $releas |
4.2 Added Remi's RPM repository
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# dnf -y install https://rpms.remirepo.net/enterprise/remi-release-8.rpm |
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# vi /etc/yum.repos.d/remi-safe.repo |
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# This repository is safe to use with RHEL/CentOS base repository # it only provides additional packages for the PHP stack # all dependencies are in base repository or in EPEL[remi-safe] name=Safe Remi's RPM repository for Enterprise Linux 8 - $basearch #baseurl=http://rpms.remirepo.net/enterprise/8/safe/$basearch/ #mirrorlist=https://rpms.remirepo.net/enterprise/8/safe/$basearch/httpsmirror mirrorlist=http://cdn.remirepo.net/enterprise/8/safe/$basearch/mirror enabled=1 ← Repository enabled (0 : Repository disabled) priority=10 ← Specify priority in the range of 1~99 gpgcheck=1 repo_gpgcheck=1 gpgkey=file:///etc/pki/rpm-gpg/RPM-GPG-KEY-remi.el8[remi-safe-debuginfo] name=Remi's RPM repository for Enterprise Linux 8 - $basearch - debuginfo baseurl=http://rpms.remirepo.net/enterprise/8/debug-remi/$basearch/ |
5.Network Settings
5.1 Host Name Change
Change the host name to Lepard to try it out
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# hostnamectl set-hostname Lepard # reboot [huong@Lepard:~]$ |
5.2 Static IP address setting
If the default setting for obtaining an IP address by DHCP was made during OS installation, change the network settings to a fixed IP address if necessary.
First, find out the name of your network interface with the following command
This time it is "ens160
This time it is "ens160
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# ip addr |
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1: lo: <LOOPBACK,UP,LOWER_UP> mtu 65536 qdisc noqueue state UNKNOWN group default qlen 1000 link/loopback 00:00:00:00:00:00 brd 00:00:00:00:00:00 inet 127.0.0.1/8 scope host lo valid_lft forever preferred_lft forever inet6 ::1/128 scope host valid_lft forever preferred_lft forever 2: ens160: <BROADCAST,MULTICAST,UP,LOWER_UP> mtu 1500 qdisc fq_codel state UP group default qlen 1000 link/ether 00:0c:29:3f:48:ad brd ff:ff:ff:ff:ff:ff inet 192.168.11.83/24 brd 192.168.11.255 scope global noprefixroute ens160 valid_lft forever preferred_lft forever |
Edit the network configuration file and change the static IP address to "192.168.11.11".
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# vi /etc/sysconfig/network-scripts/ifcfg-ens160 |
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TYPE=Ethernet PROXY_METHOD=none BROWSER_ONLY=no BOOTPROTO=none DEFROUTE=yes IPV4_FAILURE_FATAL=no IPV6INIT=no IPV6_DEFROUTE=yes IPV6_FAILURE_FATAL=no NAME=ens160 UUID=dccaab30-4028-439e-a0ec-b385375811d1 DEVICE=ens160 ONBOOT=yes IPADDR=192.168.11.11 ← change PREFIX=24 GATEWAY=192.168.11.1 DNS1=192.168.11.1 IPV6_DISABLED=yes |
To reflect the settings, do one of the following
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# systemctl restart network |
6.Vim Settings
①Install Vim
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# dnf -y install vim-enhanced |
②Apply and reflect Vim
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# vi ~/.bashrc # Alias appended to the last line alias vi='vim' # source ~/.bashrc |
③Configure Vim as a user-specific environment
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# vi ~/.vimrc |
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" vim の独自拡張機能を使用 (vi との互換性無し) set nocompatible " 文字コードを指定 set encoding=utf-8 " ファイルエンコードを指定 (先頭から順に成功するまで読み込む) set fileencodings=utf-8,iso-2022-jp,sjis,euc-jp " 自動認識させる改行コードを指定 set fileformats=unix,dos " バックアップを取得 set backup " バックアップを取得するディレクトリを指定 set backupdir=~/backup " 検索履歴を残す世代数 set history=50 " 検索時に大文字小文字を区別しない set ignorecase " 検索語に大文字を混ぜると検索時に大文字を区別する set smartcase " 検索語にマッチした単語をハイライト set hlsearch " インクリメンタルサーチを使用 set incsearch " 行番号を表示 set number " 改行 ( $ ) やタブ ( ^I ) を可視化 set list " 括弧入力時に対応する括弧を強調 set showmatch " ファイルの末尾に改行を入れない set binary noeol " 自動インデントを有効にする set autoindent " 構文ごとに色分け表示 syntax on " syntax on の場合のコメント文の色を変更 highlight Comment ctermfg=LightCyan " ウィンドウ幅で行を折り返す set wrap |