Five Essential Linux Networking Commands

Here is a summary of five widely recognized and essential Linux networking commands used for troubleshooting, information gathering, and configuration.

1. `ip` (or `ifconfig`)

This command is used to display and manipulate network interface information. ip is the modern replacement for the older, but still common, ifconfig.

Function: View IP addresses, network device status (e.g., active/inactive), and manage routing tables.
Example Usage: ip addr show to display addresses, or ifconfig for a basic overview.

2. `ping`

ping is the fundamental tool for testing network connectivity between your system and a remote host.

Function: Sends ICMP echo request packets to a target IP address or hostname and measures the time it takes for a reply (round-trip time).
Usage: ping google.com or ping 8.8.8.8.

3. `ss` (or `netstat`)

The ss (Socket Statistics) command is used to display network connections and socket information. It is the improved replacement for the older netstat.

Function: Shows listening ports, active network connections, routing tables, and interface statistics. This helps in identifying which services are running and open ports.
Example Usage: ss -tuln (shows TCP/UDP connections and listening ports in numeric format).

4. `traceroute`

This diagnostic tool traces the path (hops) packets take from your system to a specified destination host.

Function: Identifies all intermediate routers (hops) and measures the transit time to each, helping to locate where network delays or connectivity issues occur.
Usage: traceroute example.com.

5. `dig` (or `nslookup` or `host`)

These commands are used for DNS (Domain Name System) lookups to query DNS servers.

Function: Resolves hostnames to IP addresses, retrieves DNS record information (like A, MX, CNAME records), and helps troubleshoot name resolution issues.
Example Usage: dig example.com (shows detailed DNS information).