NERD IP info

IP Detector is a Chrome extension that automatically detects IPv4 addresses on any web page and highlights them so you can instantly look up their reputation and metadata via the CESNET NERD API.

The extension is built as a Manifest V3 prototype. It is safe, self-contained, and communicates with the NERD API using a user-supplied token stored only in local browser storage.

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Requirements

Valid API key is required in order to use the extension. For more information visit the official NERD website

Features

• Automatic IPv4 detection on all web pages
• Click-to-lookup on any highlighted IP — opens the popup pre-filled with the address
• Right-click "Search using NERD" on any selected text on a page — opens the popup and performs a lookup automatically
• Manual IP lookup from the popup (enter any IPv4)
• Traffic-light reputation scoring based on the rep field
  • 🔴 Red (Score > 0.5) — Malicious
  • 🟠 Orange (Score > 0.2) — Suspicious
  • 🟢 Green (Score ≤ 0.2) — Clean / Not found
  • ⚪ Gray — Unknown
• Dynamic result rendering — every field returned by the NERD API is displayed in the popup, including nested objects, dates, and arrays
• Copy raw JSON button to copy the full API response to the clipboard
• One-click NERD link to open the full IP detail page
• Recent lookups history stored locally (last 20 items)
• Scan page IPs button searches all IPs on website and shows colored icon corresponding to the reputation score
• Cached reputation results
• Dedicated options page for:
  • NERD API token input
  • Icon visibility selector (always visible / hover only)
  • Site blacklist/whitelist
  • Clear recent history
  • Delete cached IP data

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Installation

1. Clone or download this repository
2. Open Chrome and navigate to chrome://extensions/
3. Enable Developer mode
4. Click Load unpacked and select the project directory

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Usage

Page detection

• Open any page containing IPv4 addresses
• If detection is enabled, IPs are highlighted automatically
• Click the NERD icon next to an IP, or (in hover mode) move the cursor over the IP to reveal the icon and click it to open the popup and look it up

Right-click lookup (context menu)

• Highlight any text on a page (for example an IP address in an article)
• Right-click and choose "Search using NERD"
• The popup opens automatically and performs the lookup
• If the popup is already open, the lookup is run immediately without reopening

Popup lookup

• Type an IPv4 address into the input field and click Lookup
• The result card shows the traffic-light verdict, score, tags, and every field returned by the API
• Click Copy raw JSON to copy the full API response as formatted JSON to your clipboard
• Click Open in NERD to view the IP on the NERD website

Scan page IPs

• Press to perform a scan of all IPs currently rendered on page
• Each IP now has a colored icon corresponding to it's reputation score on NERD

Settings

1. Click the Settings link in the popup header
2. Paste your NERD API token and click Save Token
3. Choose your preferred Icon visibility
4. Use Clear recent history to erase the local lookup history

Security note: The API token is stored only in chrome.storage.local inside your browser. It is never sent anywhere except to the official NERD API endpoint (https://nerd.cesnet.cz).

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API Details

• Endpoint: GET https://nerd.cesnet.cz/nerd/api/v1/ip/{ip}
• Authentication: Raw token in the Authorization header (no Bearer prefix)
• Supported query types: IPv4 only

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Troubleshooting

Problem	Solution
No IPs appear on pages	Make sure detection is enabled in the popup
"Missing API key" error	Open Settings and paste a valid NERD API token, then click Save Token
Extension won’t load	Verify all files from this repository are present in the selected directory
"Request timed out" error	The API server may be slow or unreachable. Try again in a few seconds.

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Version: 1.0.0