Linux

What are Unix Domain Sockets and How They Work When we think about communication between applications, we often imagine TCP or UDP over the network. But sometimes, processes don’t need to leave the machine at all. That’s where Unix Domain Sockets (UDS) come in. What is a Unix Domain Socket? A Unix Domain Socket is a special type of inter-process communication (IPC) mechanism in Unix-like systems. Instead of using IP addresses and ports, processes talk to each other via a file path on the filesystem (e.g., /var/run/docker.sock). ...

What is mbuffer and How It Can Be Useful When working with large data transfers in Linux — for example, copying databases, streaming backups, or piping data over the network — you might face performance bottlenecks. This is where mbuffer comes in. What is mbuffer? mbuffer (short for media buffer) is a tool that adds a high-performance buffer between a producer (like tar, dd, pg_dump) and a consumer (like ssh, gzip, disk). It works like a smart middleman: it temporarily stores data in memory and forwards it more smoothly. ...

What is Syncoid and How It Can Be Useful If you use ZFS on Linux or BSD, you might have datasets and snapshots that need to be replicated between servers. Syncoid is a tool that simplifies ZFS replication and backup. Why Syncoid? Automates snapshot replication — copies snapshots between datasets or servers. Incremental transfers — only changes are sent over the network, saving bandwidth. Easy CLI usage — no need to write complex ZFS send/receive scripts. Supports remote hosts — replication over SSH is built-in. Example: Basic Syncoid Usage Assume you have a source dataset tank/data and want to replicate it to backup/data on a remote server: ...

Basic iptables Commands Every DevOps Engineer Should Know iptables is a powerful command-line utility for configuring the Linux kernel firewall. It is widely used for managing network traffic and securing Linux-based systems. Why Use iptables? Block unwanted traffic Allow specific ports Forward or redirect traffic Protect services from unauthorized access Basic iptables Syntax iptables -[A|D|I|R|L] [CHAIN] [OPTIONS] -A: Append a rule -D: Delete a rule -I: Insert a rule -R: Replace a rule -L: List rules Common Chains INPUT: Packets destined to the host OUTPUT: Packets sent from the host FORWARD: Packets routed through the host Examples List All Rules iptables -L -v -n Allow Incoming SSH (Port 22) iptables -A INPUT -p tcp --dport 22 -j ACCEPT Drop All Incoming Traffic By Default iptables -P INPUT DROP iptables -P FORWARD DROP iptables -P OUTPUT ACCEPT Allow Loopback and Established Connections iptables -A INPUT -i lo -j ACCEPT iptables -A INPUT -m conntrack --ctstate ESTABLISHED,RELATED -j ACCEPT Delete a Rule iptables -D INPUT -p tcp --dport 22 -j ACCEPT Saving and Restoring Rules Save Rules iptables-save > /etc/iptables/rules.v4 Restore Rules iptables-restore < /etc/iptables/rules.v4 Conclusion Understanding iptables helps you take full control over traffic flow in and out of your Linux systems. These basic commands will help you secure your infrastructure and troubleshoot network issues. ...