Linux Networking Essentials

Linux is widely adopted in networking tasks—from firewalls and DNS servers to secure remote connections. This guide highlights key command-line tools that help monitor network activity, transfer files, and maintain secure access across devices.

Monitoring Network Activity

ping

ping sends ICMP packets to test connectivity:

ping linuxcommand.org

Zero packet loss indicates reliable connectivity. Note that firewalls may block ICMP.

traceroute

traceroute traces packet paths through multiple routers:

traceroute slashdot.org

Shows each "hop" with IP and round-trip latency. Asterisks signal unresponsive routers.

ip

ip replaces ifconfig, controlling interfaces and routes:

ip a

Check for UP status and valid inet IPs to confirm connectivity.

netstat

netstat reports active interfaces and routing tables:

netstat -ie

netstat -r

Useful for checking the default gateway and LAN routes.

Transferring Files Over a Network

ftp

ftp transfers files via unencrypted protocol:

ftp fileserver
lcd Desktop
get ubuntu.iso

Use lftp for modern FTP with HTTPS support.

wget

wget downloads files from web or FTP sources:

wget http://linuxcommand.org/index.php

Supports background jobs, recursion, and resume.

Secure Remote Access with SSH

ssh

ssh connects to remote systems via encrypted channels:

ssh remote-sys
ssh bob@remote-sys

To run a remote command:

ssh remote-sys 'ls -la'

SSH Tunneling

ssh -X remote-sys xload

Displays GUI programs remotely via X11 forwarding.

scp and sftp

scp copies files securely:

scp remote-sys:document.txt .

sftp gives FTP-like interaction over SSH:

sftp remote-sys
get file.iso

Using SSH on Windows

PuTTY provides SSH/SCP/SFTP for Windows. Download from:

www.chiark.greenend.org.uk/~sgtatham/putty/

Conclusion

Linux’s networking arsenal—ping, traceroute, ip, netstat, wget, and ssh—offers robust control over connectivity, file operations, and remote access. Mastery of these tools empowers administrators and end users to manage networks efficiently and securely.