network-discovery

name	network-discovery
description	Network host and port discovery with nmap. Use when scanning TCP ports, enumerating hosts on a subnet, or identifying running services and versions.
user-invocable	false
allowed-tools	Bash(nmap *), Bash(ping *), Bash(arp *), Bash(ip *), Read, Grep, Glob, TodoWrite
created	"2026-01-01T00:00:00.000Z"
modified	"2026-04-25T00:00:00.000Z"
reviewed	"2026-04-25T00:00:00.000Z"

Network Discovery

When to Use This Skill

Scenario	Use this skill	Alternative
Scan all 65,535 TCP ports on a target quickly	Yes (RustScan)
Enumerate live hosts on a subnet	Yes (arp-scan-rs)
Identify running services and versions on open ports	Yes (nmap -sV)
Run NSE vulnerability or enumeration scripts	Yes (nmap --script)
Detect OS fingerprint of a remote host	Yes (nmap -O)
Discover which switch port a server is on (LLDP)		layer2-discovery (lldpcli)
Trace the route or diagnose latency to a host		network-diagnostics (trippy, gping)
Resolve DNS records for a domain		dns-tools (dog, dig)
Stress test an HTTP endpoint under load		http-load-testing (oha)
Monitor which process is using bandwidth		network-monitoring (bandwhich)
Inspect or configure the host's own IPs, links, or routes		interface-state (ip)

Core Expertise

Network discovery follows a two-phase approach: fast enumeration followed by deep analysis.

Why This Workflow

Phase	Tool	Purpose	Time
Discovery	RustScan	Scan all 65,535 TCP ports	Seconds
Discovery	arp-scan-rs	Find hosts on local network	Sub-second
Analysis	nmap	Service detection, scripts	Minutes

RustScan Advantages

• Scans all ports in 3-8 seconds (vs nmap's minutes/hours)
• Automatically chains into nmap for service detection
• Handles ulimit and batch sizing for reliability
• Written in Rust for memory safety and speed

arp-scan-rs Advantages

• Faster than traditional arp-scan
• Built-in scan profiles (default, fast, stealth)
• VLAN tagging support
• JSON output for parsing

Essential Commands

RustScan - Fast Port Discovery

# Scan single host (all 65k ports)
rustscan -a 192.168.1.100

# Scan with nmap service detection
rustscan -a 192.168.1.100 -- -sV

# Scan with nmap scripts (default safe scripts)
rustscan -a 192.168.1.100 -- -sV -sC

# Scan multiple hosts
rustscan -a 192.168.1.100,192.168.1.101

# Scan from file
rustscan -a hosts.txt

# Scan specific ports only
rustscan -a 192.168.1.100 -p 22,80,443

# Scan port range
rustscan -a 192.168.1.100 -r 1-1000

# Adjust for reliability (slower but more accurate)
rustscan -a 192.168.1.100 --ulimit 5000 --batch-size 2500

arp-scan-rs - Local Network Discovery

# Scan local network (auto-detect interface)
arp-scan-rs -l

# Scan specific interface
arp-scan-rs -i en0

# Scan specific range
arp-scan-rs 192.168.1.0/24

# Fast profile (less accurate, faster)
arp-scan-rs -l --profile fast

# Stealth profile (slower, harder to detect)
arp-scan-rs -l --profile stealth

# JSON output for parsing
arp-scan-rs -l --format json

# With VLAN tagging
arp-scan-rs -l --vlan 100

# Resolve hostnames
arp-scan-rs -l --resolve

nmap - Deep Service Analysis

Use nmap after RustScan identifies open ports:

# Service version detection
nmap -sV -p 22,80,443 192.168.1.100

# Service + default scripts
nmap -sV -sC -p 22,80,443 192.168.1.100

# OS fingerprinting (requires root)
sudo nmap -O -p 22,80,443 192.168.1.100

# Aggressive scan (version, scripts, OS, traceroute)
sudo nmap -A -p 22,80,443 192.168.1.100

# Vulnerability scripts
nmap --script vuln -p 80,443 192.168.1.100

# Specific service scripts
nmap --script http-* -p 80,443 192.168.1.100

# UDP scan (slower, requires root)
sudo nmap -sU -p 53,161 192.168.1.100

Common Patterns

Full Network Reconnaissance

# 1. Discover live hosts
arp-scan-rs -l --format json > hosts.json

# 2. Extract IPs and scan ports
arp-scan-rs -l | awk '{print $1}' > hosts.txt
rustscan -a hosts.txt -- -sV -oN scan-results.txt

# 3. Deep dive on specific services
nmap -sV -sC --script vuln -p 22 -iL hosts.txt

Quick Web Server Discovery

# Find hosts with web servers
rustscan -a 192.168.1.0/24 -p 80,443,8080,8443 -- -sV

# Enumerate web technologies
nmap --script http-headers,http-title -p 80,443 192.168.1.100

Quiet/Stealth Scanning

# Slow ARP discovery
arp-scan-rs -l --profile stealth

# RustScan with lower batch (less noisy)
rustscan -a 192.168.1.100 --batch-size 500 --ulimit 1000

# nmap timing template (T0=paranoid, T1=sneaky)
nmap -T1 -sV -p 22,80 192.168.1.100

Service-Specific Deep Dives

# SSH enumeration
nmap --script ssh-* -p 22 192.168.1.100

# SMB enumeration
nmap --script smb-* -p 445 192.168.1.100

# DNS enumeration
nmap --script dns-* -p 53 192.168.1.100

Agentic Optimizations

Context	Command
Quick port check	rustscan -a $IP -p $PORTS 2>/dev/null
Host discovery	arp-scan-rs -l --format json 2>/dev/null
Minimal output	rustscan -a $IP --greppable
JSON parsing	arp-scan-rs -l --format json | jq -r '.[].ip'
Service IDs only	nmap -sV -p $PORTS $IP -oG - | grep open
Suppress banners	rustscan -a $IP -q -- -sV
Fast local scan	arp-scan-rs -l --profile fast --format json

Quick Reference

RustScan Flags

Flag	Description
-a	Target address(es) or file
-p	Specific ports (comma-separated)
-r	Port range (e.g., 1-1000)
--ulimit	Max file descriptors (default: 5000)
--batch-size	Ports per batch (default: 4500)
--timeout	Timeout in ms (default: 1500)
-g, --greppable	Greppable output format
-q	Quiet mode
--	Pass remaining args to nmap

arp-scan-rs Flags

Flag	Description
-l	Scan local network
-i	Interface to use
--profile	Scan profile (default/fast/stealth)
--format	Output format (plain/json)
--vlan	VLAN ID for tagging
--resolve	Resolve hostnames
--timeout	Response timeout in ms

nmap Common Flags

Flag	Description
-sV	Service version detection
-sC	Default script scan
-O	OS detection (requires root)
-A	Aggressive (version + scripts + OS)
-p	Port specification
-T<0-5>	Timing template (0=slowest)
-oN	Normal output to file
-oG	Greppable output
-oX	XML output
--script	Run specific NSE scripts
-iL	Input from host list file

nmap Timing Templates

Template	Name	Use Case
-T0	Paranoid	IDS evasion
-T1	Sneaky	IDS evasion
-T2	Polite	Less bandwidth
-T3	Normal	Default
-T4	Aggressive	Fast networks
-T5	Insane	Very fast networks

Error Handling

RustScan Issues

"Too many open files":

# Reduce ulimit and batch size
rustscan -a $IP --ulimit 2000 --batch-size 1000

Slow scans:

# Increase batch size (if system allows)
rustscan -a $IP --batch-size 8000 --ulimit 10000

arp-scan-rs Issues

"Permission denied":

# ARP scanning requires raw socket access
sudo arp-scan-rs -l

No hosts found:

# Verify interface
arp-scan-rs -l -i en0  # Specify correct interface

nmap Issues

"requires root":

# OS detection and some scans need root
sudo nmap -O -p 22 $IP

Slow service detection:

# Limit version intensity
nmap -sV --version-intensity 2 -p $PORTS $IP