A comprehensive overview of the most widely used utilities for analyzing connectivity, performance, configuration, and security on Linux-based systems.
Network diagnostics are a fundamental task for system administrators, network engineers, and any professional working with IT infrastructures. In the Linux environment, there is a set of both classic and modern tools that allow you to check connectivity, analyze routes, query DNS servers, capture traffic, and much more. Below are the most important ones, along with practical usage examples.
1. Ping
Checks connectivity between two hosts using ICMP packets.
Example:
ping 8.8.8.8
Expected result:
64 bytes from 8.8.8.8: icmp_seq=1 ttl=117 time=12 ms
2. Traceroute
Shows the route that packets take to reach a destination.
Example:
traceroute google.com
Typical output:
1 192.168.0.1
2 10.10.0.1
3 172.16.20.1
...
8 google.com
3. Dig / Nslookup
DNS query tools to resolve IP addresses or specific records.
Example (dig):
dig google.com
Example (nslookup):
nslookup google.com
4. Netcat (nc) / Telnet
Verifies connectivity to specific TCP/UDP ports.
Example:
nc -zv 192.168.1.1 22
Result:
Connection to 192.168.1.1 22 port [tcp/ssh] succeeded!
5. Netstat / ss
Displays active connections, open ports, and network statistics.
Example:
netstat -tulnp
or
ss -tulnp
6. ifconfig / ip
Displays and manages network interfaces.
Example:
ifconfig
ip a
7. arp
Shows the ARP table (IP to MAC address mapping).
Example:
arp -a
8. tcpdump
Command-line tool for packet capture and analysis.
Example:
sudo tcpdump -i eth0
9. Wireshark
Graphical interface for deep packet inspection.
Typical use:
Capture from a specific interface and apply filters like:
ip.addr == 192.168.1.1
10. iperf3
Measures network performance between two devices.
Example:
Server:
iperf3 -s
Client:
iperf3 -c 192.168.1.1
11. iftop / nethogs
Real-time network traffic monitoring.
Example:
sudo iftop
sudo nethogs
12. systemd-resolve
Displays DNS resolution statistics.
Example:
systemd-resolve --statistics
13. journalctl -u NetworkManager
Views logs for the network manager service.
Example:
journalctl -u NetworkManager
14. glances
Real-time monitoring of system resources, including networking.
Example:
glances
15. nmap
Scans networks, ports, and identifies services.
Example:
nmap -sP 192.168.1.0/24
nmap -sV 192.168.1.1
Final Thoughts
Mastering these tools not only helps solve common connectivity problems but also improves security, performance, and provides a clear overview of the network’s status. While many of these utilities are also available in Windows, the Linux environment offers greater flexibility and power, especially for automation and scripting.
For networking professionals, a thorough understanding of these tools is essential. Combined, they enable efficient diagnostic workflows without relying on heavy graphical interfaces.
