Networking Utilities

list of essential networking utilities/tools every developer, system admin, or DevOps engineer should know

Tool	Purpose	Example Usage
ping	Test connectivity and measure latency	`ping` `google.com`
traceroute (or `tracert` on Windows)	Trace the path of packets to a host	`traceroute` `google.com`
nslookup / dig	DNS query tool to resolve domain names	`nslookup` `openai.com` / `dig` `openai.com`
ip / ifconfig	View and configure IP addresses	`ip a` or `ifconfig`
netstat	View network connections, ports, and routing	`netstat -tuln`
ss	Modern replacement for `netstat` (faster)	`ss -tulnp`
nmap	Port scanner, service/version detection	`nmap -sV 192.168.1.1`
tcpdump	Capture and analyze network packets	`sudo tcpdump -i eth0`
wireshark	GUI tool for packet inspection	Start via GUI and capture packets
telnet / nc (netcat)	Test open ports or connect to a server manually	`nc -zv 192.168.1.100 80`
curl / wget	Test HTTP/FTP requests from the command line	`curl` `http://example.com`
iptables / ufw / firewalld	Linux firewall management tools	`sudo ufw status`
arp	View or modify ARP table	`arp -a`
route / ip route	Show routing table	`ip route`
hostname	Show or set system's hostname	`hostname`
ethtool / mii-tool	Ethernet diagnostics	`ethtool eth0`

nmap

Nmap (Network Mapper) is a free and powerful tool used to scan networks, find connected devices, check open ports, and identify running services. It's helpful for network admins and security testers.

Nmap is used to scan a network or server to find which ports are open, which services are running, and then you can take action to secure your system.

Here are some important Nmap commands you should learn:

Purpose	Command	Explanation
Scan common ports	`nmap 192.168.0.1`	Scans top 1000 ports of a host
Scan all ports	`nmap -p- 192.168.0.1`	Scans all 65535 ports
Check specific ports	`nmap -p 22,80,443 192.168.0.1`	Only scan selected ports
Detect service versions	`nmap -sV 192.168.0.1`	Shows version info of running services
OS detection	`nmap -O 192.168.0.1`	Tries to guess operating system
Full scan (Aggressive)	`nmap -A 192.168.0.1`	Does OS, version, script, and traceroute scan
Stealth scan (TCP SYN)	`nmap -sS 192.168.0.1`	Quick and less detectable scan
Scan an entire subnet	`nmap 192.168.0.0/24`	Scans all devices in the subnet
Save results	`nmap -oN result.txt 192.168.0.1`	Saves scan result to a fil

bellow image shows all network host
it also show which port are open in all nodes

here how we can check one particular host details

tcpdump

is a network packet analyzer — a command-line tool used to capture and inspect network traffic going through your system. It's widely used for network debugging, security analysis, and troubleshooting.

wireshark

Wireshark is a GUI-based network protocol analyzer. It captures packets like tcpdump, but it displays them in a human-readable, structured, and color-coded format.