Go Concurrent Port Scanner

A high-performance TCP connect port scanner written in Go using a worker pool concurrency model.
This tool scans a target host for open TCP ports and supports CLI configuration, service detection, and exportable results.

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🚀 Features

• Concurrent TCP scanning using worker pools
• Configurable number of workers
• Adjustable timeout per connection
• Fast scan mode (reduced timeout)
• Service name detection (common ports)
• Progress indicator during scan
• JSON and CSV export support
• Clean CLI interface

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🧠 How it works

This scanner uses a worker pool architecture:

Main Goroutine
  ├── Job Channel (ports)
  ├── Worker Goroutines (TCP scanners)
  └── Result Channel (scan results)

Each worker:
1. Receives a port from the job queue
2. Attempts a TCP connection using net.DialTimeout
3. Returns whether the port is open

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⚙️ Usage

Basic scan

go run . -host scanme.nmap.org

Custom port range

go run . -host scanme.nmap.org -ports 1-2000

Increase concurrency

go run . -host scanme.nmap.org -workers 200

Faster scan mode

go run . -host scanme.nmap.org -fast

Save results to file

CSV:

go run . -host scanme.nmap.org -out results.csv

JSON:

go run . -host scanme.nmap.org -json -out results.json

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📊 Example Output

====================================
Go Concurrent Port Scanner
====================================
Target     : scanme.nmap.org
Ports      : 1-1024
Workers    : 100
Timeout    : 300ms

[OPEN] 22   /tcp  ssh
[OPEN] 80   /tcp  http

Scanning... 1024/1024 ports

====================================
Scan Complete
====================================
Open Ports    : 2
Ports Scanned : 1024
Elapsed Time  : 1.7s

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⚡ Technical Details

• Worker pool concurrency model
• Buffered channels for job distribution
• net.DialTimeout TCP connect scanning
• Atomic counters for safe progress tracking

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⚠️ Notes

• Only scan systems you own or are authorized to test
• Some ports may appear closed due to timeout limits
• Fast mode may introduce false negatives

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🧪 Test Target

scanme.nmap.org

Provided by Nmap for educational purposes.