Here’s the automated optimization script for Debian 11 on a KVM VPSï¼
Save the following script as debian11_optimize.sh and run it:
#!/bin/bash
echo "🚀 Starting Debian 11 CLI Optimization for KVM VPS" # 1. Update System apt update && apt upgrade -y apt autoremove --purge -y apt clean # 2. Remove Unnecessary Packages apt remove --purge -y apport popularity-contest avahi-daemon cups rpcbind xserver-common x11-common # 3. Install KVM-Optimized Kernel apt install -y linux-image-cloud-amd64 # 4. Update GRUB and Apply Optimizations sed -i 's/GRUB_CMDLINE_LINUX_DEFAULT="[^"]*/& mitigations=off noibrs no_stf_barrier/g' /etc/default/grub update-grub # 5. Enable BBR TCP Congestion Control echo "net.core.default_qdisc=fq" >> /etc/sysctl.conf echo "net.ipv4.tcp_congestion_control=bbr" >> /etc/sysctl.conf sysctl -p # 6. Configure DNS for Faster Resolution sed -i 's/#DNS=/DNS=8.8.8.8 1.1.1.1/g' /etc/systemd/resolved.conf systemctl restart systemd-resolved # 7. SSH Hardening - Change SSH Port sed -i 's/#Port 22/Port 22022/g' /etc/ssh/sshd_config systemctl restart ssh # 8. Install Fail2Ban to Prevent SSH Brute Force apt install -y fail2ban # 9. Setup Firewall with UFW apt install -y ufw ufw allow 22022/tcp ufw allow 80/tcp ufw allow 443/tcp ufw enable # 10. Disk & I/O Optimization tune2fs -o journal_data_writeback /dev/vda1 tune2fs -m 1 /dev/vda1 echo "vm.swappiness=10" >> /etc/sysctl.conf sysctl -p # 11. CPU & Memory Optimization - Disable Unnecessary Services systemctl disable --now systemd-resolved avahi-daemon cups echo "performance" | sudo tee /sys/devices/system/cpu/cpu*/cpufreq/scaling_governor echo "✅ Optimization Complete! Please reboot your server."
Article 9 can be removed, because the firewall is not properly set up, it is easy for you to not even be able to log in to SSH.
1.How to Run the Script:
Create the script file:
nano debian11_optimize.sh
2.Paste the script content into the file, save, and exit.
3.Make the script executable:
chmod +x debian11_optimize.sh
4.Run the script with sudo:
sudo ./debian11_optimize.sh
This will automatically apply all optimizations for your Debian 11 CLI on a KVM VPS. After the script finishes, a reboot is recommended for all settings to take effect.