ip-scan

A lightweight Bash utility for scanning IP CIDR ranges, identifying hosts with port 443 (HTTPS) open, and recording those that respond with HTTP 403.

This tool is designed for infrastructure audits, CDN/IP range analysis, and security research where quick HTTPS reachability and response-code filtering is required.

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Features

• 🚀 High‑performance scanning using masscan
• 🔐 HTTPS validation using curl
• 📄 CSV output for easy post‑processing
• 🧾 Comment‑aware CIDR input file
• ⚙️ Simple, dependency‑light Bash script

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Requirements

• Linux system
• masscan
• curl
• Root or sudo access (required by masscan)

Install dependencies

# Debian / Ubuntu
sudo apt update && sudo apt install -y masscan curl

# RHEL / CentOS
sudo yum install -y masscan curl

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Usage

1. Prepare CIDR list

Create a text file (for example cidrs.txt) with one CIDR per line:

# Example CIDRs
192.168.1.0/24
10.0.0.0/16
172.16.5.10/32

• Lines starting with # are ignored
• IPv4 CIDRs only

2. Run the scanner

sudo bash check_ips.sh cidrs.txt

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Output

• Terminal: live output of IPs returning HTTP 403
• result.csv: CSV file with a single column:

ip
1.2.3.4
5.6.7.8

The file is created (or overwritten) in the current working directory.

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How It Works

1. masscan scans all provided CIDRs for port 443 with a controlled rate
2. IPs with an open HTTPS port are extracted
3. Each IP is queried via HTTPS using curl
   • TLS errors are ignored
   • Timeouts are enforced
4. Hosts returning HTTP 403 are saved to result.csv

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Configuration

You can tune the following parameters directly inside check_ips.sh:

Setting	Default	Description
--rate	1000	masscan packets per second
--connect-timeout	3	curl connection timeout (seconds)
--max-time	5	curl max request time (seconds)
-p	443	port to scan

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Use Cases

• CDN / WAF IP range validation
• Cloud provider IP inspection
• Security research and filtering
• HTTPS endpoint discovery

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Safety & Ethics

⚠️ Only scan networks you own or are authorized to test.

Unauthorized scanning may violate laws, provider policies, or acceptable‑use rules.

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License

Licensed under the GNU General Public License v3.0.

See LICENSE for details.

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Contributing

Pull requests are welcome.

If you plan a significant change, please open an issue first to discuss it.

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Author

Mohammad Hassan Roohbakhsh
GitHub: https://github.com/roohbakhsh