Ranjan

DevOps architect and Linux sysadmin specializing in server hardening, OpenLiteSpeed performance optimization, and free cloud hosting infrastructure.

Linux Kernel Hardening: 10 Critical sysctl.conf Tweaks to Prevent SYN Floods & Spoofing

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Quick Technical Answer: To harden the Linux kernel against network attacks, edit /etc/sysctl.d/99-security.conf. Enable TCP SYN cookies with net.ipv4.tcp_syncookies = 1 to survive SYN floods, enable reverse path filtering with net.ipv4.conf.all.rp_filter = 1 to block IP spoofing, disable ICMP redirects (accept_redirects = 0), and maximize ASLR memory protection with kernel.randomize_va_space = 2. Apply immediately with … Read more

Top 5 Terminal Monitoring Tools: htop, btop, glances, iotop & vmstat Compared

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Quick Technical Answer: For daily interactive process management, htop is the essential baseline. For modern visual aesthetics with GPU, disk, and network graphs, use btop (sudo apt install btop). If you need per-process disk read/write bandwidth diagnosis, use iotop. To export metrics over a web interface or REST API, install glances. For lightweight zero-overhead kernel … Read more

How to Enable TCP BBR Congestion Control on Ubuntu VPS for 2x Network Throughput

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Quick Technical Answer: To activate Google’s TCP BBR on Ubuntu 24.04/22.04 LTS: Append net.core.default_qdisc=fq and net.ipv4.tcp_congestion_control=bbr to /etc/sysctl.conf. Apply the changes immediately with sudo sysctl -p. Verify active status with sysctl net.ipv4.tcp_congestion_control; the terminal will return bbr. Why Legacy TCP CUBIC Fails on Modern Internet Connections For over two decades, Linux distributions relied on TCP … Read more

How to Use Rsync Over SSH for Automated Server-to-Server Backups and Sync

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Quick Technical Answer: To synchronize files securely between two Linux VPS servers over SSH, use the standard command: rsync -avzP -e “ssh -p 22” /local/source/ user@remote_ip:/remote/destination/. The flags -a preserves permissions and timestamps, -v enables verbose output, -z enables gzip transmission compression, and -P preserves partial transfers with a live progress bar. To make it … Read more

How to Resize and Expand LVM Disk Partitions on Linux VPS Without Rebooting

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Quick Technical Answer: To expand an LVM partition on a running Linux VPS without rebooting: First, rescanning the SCSI block device using echo 1 | sudo tee /sys/class/block/sdX/device/rescan. If using a partition table, expand it with sudo growpart /dev/sdX 3. Then, expand the Physical Volume with sudo pvresize /dev/sdX3. Next, extend the Logical Volume to … Read more

How to Configure Logrotate and Manage systemd Journalctl to Prevent Full Disks

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Quick Technical Answer: To immediately reclaim disk space from bloated logs on Linux, vacuum the systemd journal using sudo journalctl –vacuum-size=200M. Then, cap future growth permanently by setting SystemMaxUse=250M in /etc/systemd/journald.conf and restarting with sudo systemctl restart systemd-journald. For application logs in /var/log/, create a rule in /etc/logrotate.d/myapp specifying daily, rotate 7, compress, delaycompress, and … Read more

Linux systemd Service Management: How to Create and Manage Custom Background Daemons

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Quick Technical Answer: To create a persistent background daemon on modern Linux (Ubuntu/Debian/RHEL), create a unit file at /etc/systemd/system/yourservice.service. Define [Unit] for metadata and dependencies, [Service] with ExecStart=/path/to/binary, Restart=always, and an isolated User=appuser, followed by [Install] with WantedBy=multi-user.target. Run sudo systemctl daemon-reload, then activate it using sudo systemctl enable –now yourservice. Why systemd Is the … Read more

How to Install Portainer on Linux VPS for Visual Docker Management

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Quick Technical Answer: To deploy Portainer Community Edition (CE) on Ubuntu 24.04/22.04 LTS, first verify Docker is installed. Create a persistent volume with docker volume create portainer_data, then launch the official container with docker run -d -p 8000:8000 -p 9443:9443 –name portainer –restart=always -v /var/run/docker.sock:/var/run/docker.sock -v portainer_data:/data portainer/portainer-ce:latest. Access the management dashboard securely at https://YOUR_SERVER_IP:9443 … Read more

How to Set Up Free Let’s Encrypt SSL in DirectAdmin: Complete Guide (2026)

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Time to Install: Under 3 minutes directly from the DirectAdmin browser interface. Certificate Authority: Free, automated Let’s Encrypt certificates with 2048/4096-bit RSA encryption. Auto-Renewal: DirectAdmin runs an internal daily cron job that renews all active certificates automatically 30 days before expiration. HTTPS Enforcement: A single toggle in … Read more

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