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# IP
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IP is a comprehensive Node.js library providing utilities for IPv4 and IPv6 address manipulation, validation, conversion, and network operations. It supports address format conversion between strings, buffers, and long integers, subnet calculations, CIDR operations, network masking, and network interface queries.
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## Package Information
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- **Package Name**: ip
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- **Package Type**: npm
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- **Language**: JavaScript
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- **Installation**: `npm install ip`
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## Core Imports
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```javascript
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const ip = require('ip');
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```
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For ES modules:
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```javascript
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import * as ip from 'ip';
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// or 
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import ip from 'ip';
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```
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## Basic Usage
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```javascript
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const ip = require('ip');
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// Get local IP address
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console.log(ip.address()); // Your local IP address
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// Validate IP formats
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console.log(ip.isV4Format('192.168.1.1')); // true
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console.log(ip.isV6Format('::1')); // true
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// Convert between formats
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const buffer = ip.toBuffer('127.0.0.1');
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console.log(ip.toString(buffer)); // '127.0.0.1'
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// Subnet operations
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const subnet = ip.subnet('192.168.1.134', '255.255.255.192');
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console.log(subnet.networkAddress); // '192.168.1.128'
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console.log(subnet.contains('192.168.1.150')); // true
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// CIDR operations
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console.log(ip.cidr('192.168.1.134/26')); // '192.168.1.128'
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// Check private addresses
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console.log(ip.isPrivate('192.168.1.1')); // true
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console.log(ip.isPrivate('8.8.8.8')); // false
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```
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## Architecture
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The IP library is built around several key functional areas:
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- **Address Conversion**: Convert between string, buffer, and long integer representations
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- **Address Validation**: Validate IP address formats and classify address types
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- **Network Operations**: Perform subnet calculations, CIDR operations, and network masking
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- **Bitwise Operations**: Apply bitwise NOT and OR operations to IP addresses
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- **Network Interface Operations**: Query local network interfaces for IP addresses
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## Capabilities
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### Address Conversion
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Core functions for converting IP addresses between different representations including strings, buffers, and long integers.
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```javascript { .api }
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function toBuffer(ip, buff, offset);
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function toString(buff, offset, length);
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function toLong(ip);
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function fromLong(ipl);
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function normalizeToLong(addr);
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```
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[Address Conversion](./address-conversion.md)
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### Address Validation
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Functions for validating IP address formats and classifying addresses as private, public, or loopback.
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```javascript { .api }
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function isV4Format(ip);
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function isV6Format(ip);
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function isEqual(a, b);
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function isPrivate(addr);
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function isPublic(addr);
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function isLoopback(addr);
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```
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[Address Validation](./address-validation.md)
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### Network Operations
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Comprehensive subnet calculation, CIDR operations, and network masking functionality for network analysis.
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```javascript { .api }
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function fromPrefixLen(prefixlen, family);
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function mask(addr, mask);
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function cidr(cidrString);
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function subnet(addr, mask);
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function cidrSubnet(cidrString);
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```
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[Network Operations](./network-operations.md)
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### Bitwise Operations
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Bitwise manipulation functions for IP addresses including NOT and OR operations.
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```javascript { .api }
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function not(addr);
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function or(a, b);
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```
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[Bitwise Operations](./bitwise-operations.md)
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### Network Interface Operations
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Functions for querying local network interfaces and retrieving IP addresses from the system.
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```javascript { .api }
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function address(name, family);
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function loopback(family);
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```
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[Network Interface Operations](./network-interfaces.md)