RHELでのセキュリティネットワーク設定 – アクセス制御と監視をはじめよう

sudo systemctl status firewalld

sudo systemctl enable firewalld --now

sudo firewall-cmd --permanent --add-service=http
sudo firewall-cmd --permanent --add-service=https
sudo firewall-cmd --reload

sudo firewall-cmd --permanent --add-port=8080/tcp
sudo firewall-cmd --reload

sudo firewall-cmd --list-all

sestatus

sudo setenforce 1
sudo nano /etc/selinux/config
# SELINUX=enforcing を確認または変更

sudo nano /etc/ssh/sshd_config

# ポート変更例:
Port 2222

# ルートログイン無効化
PermitRootLogin no

# 再起動
sudo systemctl restart sshd

sudo dnf install epel-release -y
sudo dnf install fail2ban -y
sudo systemctl enable fail2ban --now

sudo nano /etc/fail2ban/jail.local
[sshd]
enabled = true
port = 2222
maxretry = 5
bantime = 600

sudo systemctl restart fail2ban

sudo dnf install tcpdump -y
sudo tcpdump -i eth0

sudo tcpdump port 80

sudo dnf install net-tools nmap -y
netstat -tuln
nmap -sS localhost

sudo iptables -A INPUT -p tcp --tcp-flags ALL NONE -j DROP
sudo iptables -A INPUT -p tcp --tcp-flags SYN,ACK SYN,ACK -m limit --limit 1/s -j ACCEPT
sudo iptables-save > /etc/iptables/rules.v4

sudo tail -f /var/log/messages
sudo journalctl -xe

sudo nano /etc/logrotate.conf

sudo dnf install dnf-automatic -y
sudo systemctl enable --now dnf-automatic.timer