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Complete IP address lookup guide with geolocation, security analysis, and threat intelligence for 2025
Network Security Guide

IP Address Lookup Complete Guide: Geolocation, Security & Network Intelligence (2025)

48 min read
5721 words
Tags: # ip lookup# ip geolocation# ip address tracker# vpn detection# proxy detection# network security# fraud prevention# asn lookup# reverse dns# threat intelligence# ipv4# ipv6
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IP Address Lookup Complete Guide: Geolocation, Security & Network Intelligence (2025)

Your e-commerce site just processed a $5,000 order. The billing address says New York, but the IP address traces to Lagos, Nigeria. Your fraud detection system flags it—but is it actually fraud, or just a legitimate customer using a VPN?

Your website suddenly slows to a crawl. Server logs show thousands of requests from 47 different IP addresses across 12 countries. Your hosting provider threatens suspension for suspicious activity. You need to identify the attack source, fast.

You’re launching a new streaming service with geo-restricted content. Users in restricted countries are accessing your platform using VPNs and proxies. Your licensing agreements mandate geographic enforcement. How do you detect and block them without affecting legitimate users?

The reality is stark: 43% of online fraud involves IP address spoofing or geolocation mismatches according to LexisNexis research. DDoS attacks cost businesses $120,000 per hour on average. Meanwhile, false positives from overly aggressive IP blocking lose you 15-25% of legitimate customers. The difference between security and lost revenue is knowing exactly what an IP address reveals—and what it doesn’t.

This guide teaches you everything about IP address lookup, from fundamentals to advanced threat intelligence. You’ll learn how IP geolocation actually works behind the scenes with GeoIP databases and ASN routing tables, how to detect VPNs, proxies, and Tor nodes with 95%+ accuracy, how to prevent fraud by matching IP location with billing addresses and device fingerprints, how to trace malicious traffic using WHOIS, reverse DNS, and threat intelligence feeds, how to implement geofencing and content restrictions while minimizing false positives, and how to optimize your security stack with automated IP reputation checking and rate limiting.

By the end, you’ll diagnose IP-based threats faster than most security teams can open their SIEM dashboard. Let’s begin.

Quick Answer: IP Lookup Essentials

Don’t have time for 12,000 words? Here’s what you need to know right now:

  • What IP lookup reveals: Geographic location (city/country), ISP/hosting provider, network owner (ASN), VPN/proxy detection, threat intelligence, reverse DNS hostname
  • Accuracy limitations: City-level accuracy is 55-80% (MaxMind data), country-level is 95-99%, VPNs/proxies deliberately hide true location
  • Best lookup tool: Use our IP Address Lookup Tool for instant geolocation + threat intelligence, combined with WHOIS lookup for detailed network ownership
  • VPN detection methods: Database matching (95% accuracy), latency analysis, WebRTC leak detection, DNS leak testing, behavioral fingerprinting
  • Common use cases: Fraud prevention, content personalization, security monitoring, regulatory compliance (GDPR), license enforcement
  • Free vs Premium APIs: Free (IPinfo.io 50k/month) provides basic location, Premium (MaxMind, IPQualityScore) adds fraud scoring, bot detection, proxy databases
  • Privacy considerations: IP addresses are personal data under GDPR Article 4(1)—log retention and processing require legitimate interest or consent

Still here? Perfect. Let’s master IP address intelligence from fundamentals to advanced security applications.

What is an IP Address? (The Fundamentals)

IP Address Definition and Format

An IP (Internet Protocol) address is a unique numerical identifier assigned to every device connected to the internet. Think of it as a phone number for your computer, smartphone, or server—it enables data to route correctly between millions of devices worldwide.

There are two IP address versions in use today:

IPv4 (Internet Protocol version 4)

Format: Four decimal numbers (0-255) separated by dots, called dotted-decimal notation

Example: 192.168.1.1, 8.8.8.8 (Google DNS), 142.250.185.78 (Google.com)

Address Space: 32-bit addresses = 4,294,967,296 possible addresses (2³²)

Structure Breakdown:

203.0.113.45
│││ │ │││ ││
└┴┴─┼─┴┴┴─┼┴─ 4 octets (bytes)
    │     │
Network │  Host portion (identifies specific device)
portion │
        └─── Subnet (192.168.x.x are private, non-routable)

Address Classes (Legacy Classification):

  • Class A: 1.0.0.0 to 126.0.0.0 - Large networks (16 million hosts)
  • Class B: 128.0.0.0 to 191.255.0.0 - Medium networks (65k hosts)
  • Class C: 192.0.0.0 to 223.255.255.0 - Small networks (254 hosts)
  • Class D: 224.0.0.0 to 239.255.255.255 - Multicast
  • Class E: 240.0.0.0 to 255.255.255.255 - Reserved for research

Special Reserved Ranges (RFC 1918):

  • 10.0.0.0/8 - Private networks (10.0.0.0 to 10.255.255.255)
  • 172.16.0.0/12 - Private networks (172.16.0.0 to 172.31.255.255)
  • 192.168.0.0/16 - Home/office LANs (192.168.0.0 to 192.168.255.255)
  • 127.0.0.0/8 - Loopback addresses (127.0.0.1 = localhost)
  • 169.254.0.0/16 - Link-local addresses (APIPA/DHCP failure)

IPv4 Exhaustion: The IPv4 address space was exhausted in 2011 when IANA allocated the last /8 blocks to regional registries. This scarcity drives the transition to IPv6 and necessitates technologies like NAT (Network Address Translation) and CGNAT (Carrier-Grade NAT).

IPv6 (Internet Protocol version 6)

Format: Eight groups of four hexadecimal digits separated by colons

Example: 2001:0db8:85a3:0000:0000:8a2e:0370:7334 (full form)

Shortened: 2001:db8:85a3::8a2e:370:7334 (compressed form—consecutive zero groups become ::)

Address Space: 128-bit addresses = 340,282,366,920,938,463,463,374,607,431,768,211,456 addresses (2¹²⁸)

That’s 340 undecillion addresses—approximately 670 quadrillion addresses per square millimeter of Earth’s surface.

Common IPv6 Prefixes:

  • 2001::/32 - Production internet addresses
  • 2002::/16 - 6to4 transition mechanism
  • fc00::/7 - Unique local addresses (ULA, similar to IPv4 private)
  • fe80::/10 - Link-local addresses
  • ff00::/8 - Multicast addresses
  • ::1/128 - Loopback (equivalent to 127.0.0.1)

Adoption Status: As of 2025, approximately 45% of Google users access services via IPv6, but many networks still rely on IPv4 with NAT. Check your own IPv6 connectivity with our What is My IP tool.

How IP Addresses Are Assigned (IP Allocation Hierarchy)

IP address assignment follows a hierarchical structure managed by international organizations:

Global Allocation Hierarchy:

┌─────────────────────────────────────────┐
│  IANA (Internet Assigned Numbers        │
│  Authority) - Managed by ICANN          │
│  Allocates /8 blocks to RIRs            │
└────────────────┬────────────────────────┘
                 │
         ┌───────┴───────┬───────────┬────────────┬────────────┐
         │               │           │            │            │
    ┌────▼────┐    ┌────▼────┐ ┌───▼─────┐ ┌────▼─────┐ ┌───▼─────┐
    │ ARIN    │    │ RIPE NCC│ │ APNIC   │ │ LACNIC   │ │ AFRINIC │
    │ N.America│   │ Europe  │ │ Asia-   │ │ Latin    │ │ Africa  │
    │          │    │ Middle  │ │ Pacific │ │ America  │ │         │
    │          │    │ East    │ │         │ │ Caribbean│ │         │
    └────┬────┘    └────┬────┘ └───┬─────┘ └────┬─────┘ └───┬─────┘
         │              │           │            │            │
         │    Allocate /12 to /16 blocks to ISPs/LIRs         │
         └──────────────┴───────────┴────────────┴────────────┘
                                    │
                           ┌────────▼─────────┐
                           │  ISPs/Hosting    │
                           │  Providers       │
                           │  Assign IPs to   │
                           │  end users       │
                           └──────────────────┘

Regional Internet Registries (RIRs):

  • ARIN - North America, Caribbean, North Atlantic islands
  • RIPE NCC - Europe, Middle East, Central Asia
  • APNIC - Asia-Pacific region
  • LACNIC - Latin America, Caribbean
  • AFRINIC - Africa

IP Assignment Process:

  1. RIR Allocation: IANA allocates large blocks (/8 prefixes) to RIRs
  2. LIR Assignment: RIRs allocate smaller blocks (/12 to /22) to Local Internet Registries (ISPs, hosting providers, large enterprises)
  3. End User Assignment: ISPs assign individual IPs or small blocks to customers
  4. Dynamic vs Static: Residential users typically get dynamic IPs (change on router restart), businesses purchase static IPs (permanent assignment)

WHOIS Database: Every IP allocation is recorded in WHOIS databases maintained by RIRs. This public registry enables network attribution and abuse reporting. Query WHOIS data with our DNS Lookup tool or via command line:

# Query WHOIS for IP ownership
whois 8.8.8.8

# Expected output includes:
# Organization: Google LLC
# Network Range: 8.8.8.0 - 8.8.8.255
# ASN: AS15169
# Country: US

Understanding IP allocation is critical for threat intelligence—attackers often use specific ASNs (hosting providers) or countries for malicious activity.

How IP Geolocation Works (The Technical Details)

IP geolocation maps IP addresses to physical locations. But how do services like ours determine that 203.0.113.42 is in Paris, France? The answer involves multiple data sources, complex algorithms, and inherent accuracy limitations.

GeoIP Database Architecture

Core Concept: IP addresses are allocated in contiguous blocks (CIDR ranges) to specific organizations and regions. GeoIP databases map these ranges to geographic coordinates using:

1. RIR Allocation Records (Most Reliable)

Regional Internet Registries publish IP allocation data including:

  • IP Range: CIDR block (e.g., 203.0.113.0/24)
  • Organization: Company/ISP name
  • Country: ISO 3166-1 alpha-2 code
  • Registration Date: When block was allocated

Accuracy: Country-level 95-99% (directly from RIR records)

2. BGP Routing Tables (Network-Level Geolocation)

Border Gateway Protocol (BGP) announces which Autonomous Systems (AS) handle traffic for specific IP ranges. By analyzing BGP announcements from thousands of routers worldwide, providers infer geographic distribution.

Data Sources:

Example BGP Path:

AS Path: 15169 (Google) → 1299 (Telia) → 3356 (Level3) → 7922 (Comcast)
Geographic Inference: AS15169 peers primarily in North America/Europe

3. Active Probing and Latency Measurement

Geolocation providers ping IP addresses from known locations worldwide and measure Round-Trip Time (RTT). Lower latency suggests geographic proximity.

Speed of Light Constraint: Network packets travel at ~200,000 km/s in fiber. A 50ms RTT suggests distance under 5,000 km.

Traceroute Analysis:

traceroute -I 8.8.8.8

# Output shows router hops with hostnames:
# rtr-chi01.google.com (Chicago datacenter)
# rtr-ord.google.com (O'Hare peering point)
# dns.google (final destination)

Hostname patterns like chi01 (Chicago), lax (Los Angeles), fra (Frankfurt) reveal location clues.

4. User-Contributed Data and WiFi Geolocation

Services like MaxMind and IP2Location crowdsource location data:

  • WiFi MAC addresses mapped to GPS coordinates (Google/Apple street-level mapping)
  • Mobile carrier cell towers with known locations
  • User submissions correcting inaccurate database entries

5. Historical Traffic Patterns

Machine learning models analyze:

  • Timezone activity patterns (when users are active)
  • Language preferences from HTTP Accept-Language headers
  • Local service usage (payment processors, delivery companies)

Major GeoIP Database Providers

MaxMind GeoIP2 (Industry Standard)

Database Tiers:

  • GeoLite2 (Free): Country, city, ASN data. Updated weekly. Download
  • GeoIP2 Precision (Paid): 99.9% country accuracy, 80% city accuracy, ISP details, proxy detection
  • GeoIP2 Anonymous IP: VPN/proxy/Tor detection, hosting provider identification

Accuracy Metrics (MaxMind Published Data):

  • Country Level: 99.8% accuracy
  • State/Region: 93% within 500km radius (USA)
  • City Level: 81% within 50km radius (USA)
  • Postal Code: 10% exact match (highly variable)

API Example:

import geoip2.database

reader = geoip2.database.Reader('/path/to/GeoLite2-City.mmdb')
response = reader.city('203.0.113.42')

print(response.country.name)  # 'France'
print(response.city.name)  # 'Paris'
print(response.location.latitude)  # 48.8566
print(response.location.longitude)  # 2.3522
print(response.postal.code)  # '75001'

IP2Location (Alternative Provider)

Strengths:

  • IPv6 coverage superior to MaxMind in some regions
  • ISP and usage type classification (commercial, residential, cellular)
  • Threat database with known proxies and VPNs

Database Formats: CSV, MMDB (MaxMind compatible), BIN (proprietary)

IPinfo.io (Developer-Friendly API)

Free Tier: 50,000 requests/month with basic geolocation

API Response Example:

{
  "ip": "8.8.8.8",
  "hostname": "dns.google",
  "city": "Mountain View",
  "region": "California",
  "country": "US",
  "loc": "37.4056,-122.0775",
  "org": "AS15169 Google LLC",
  "postal": "94043",
  "timezone": "America/Los_Angeles"
}

Paid Features: Privacy detection (VPN/proxy), ASN details, abuse contact info, company intelligence

Accuracy Limitations and Edge Cases

Why IP Geolocation Isn’t Perfect:

1. Mobile Carrier CGN (Carrier-Grade NAT)

Problem: Millions of mobile users share a single public IP address

Effect: Geolocation shows carrier’s gateway location, not user’s true location

Detection: isp field shows “Verizon Wireless”, connection_type = cellular

2. VPN and Proxy Services

Problem: User deliberately masks location by routing through VPN server

Effect: IP shows VPN datacenter, not user’s actual country

Detection: Database matching (known VPN IP ranges), latency inconsistencies, WebRTC leaks

Common VPN Providers:

  • ExpressVPN, NordVPN, Surfshark (commercial)
  • ProtonVPN, Mullvad (privacy-focused)
  • Corporate VPNs (employees appear to be at headquarters)

3. Cloud Hosting and CDN

Problem: Website hosted on AWS/Cloudflare shows datacenter location, not business location

Effect: amazon.com IP traces to AWS us-east-1 (Virginia), not Seattle headquarters

Detection: ASN analysis—AS16509 Amazon.com Inc. indicates AWS hosting

4. IPv6 Privacy Extensions

Problem: RFC 4941 randomizes IPv6 interface identifiers for privacy

Effect: Same device gets different IPv6 addresses daily

Detection: /64 prefix remains constant (network portion), but host portion changes

5. Satellite and Maritime Internet

Problem: Satellite uplink location doesn’t match user location

Effect: Users on cruise ships or rural satellite ISPs show gateway location

Detection: High latency (500-800ms), ISP name contains “satellite”

Practical Accuracy Expectations:

  • Country-level: 95-99% reliable (use for regulatory compliance, currency selection)
  • City-level: 55-80% accuracy within 25-50 km (use for weather, localized marketing)
  • Street-level: Not possible from IP alone (requires GPS, WiFi triangulation)
  • Real-time movement: IP doesn’t update instantly—mobile users may show stale location

Test Your Own IP: Use our What is My IP Address tool to see what geolocation services detect about your connection, including potential VPN/proxy flags.

How to Perform IP Address Lookup (Methods and Tools)

Multiple methods exist for IP lookup, from web-based tools to command-line utilities to programmatic APIs. Each approach has specific use cases, accuracy trade-offs, and compliance considerations.

Online IP Lookup Tools (No Installation Required)

Our IP Address Lookup Tool

URL: https://orbit2x.com/ip-lookup

Features:

  • Instant Geolocation: City, region, country, coordinates, timezone
  • Network Intelligence: ISP name, organization, ASN number, CIDR range
  • Security Analysis: VPN/proxy detection, threat score, abuse history
  • Reverse DNS: PTR record lookup for hostname verification
  • Privacy-Focused: No data logging, GDPR compliant
  • Both IPv4 & IPv6: Full support for modern networks

Use Cases:

  • Security teams investigating suspicious login attempts
  • Fraud analysts verifying billing address matches
  • Marketers understanding visitor demographics
  • Developers testing geolocation features
  • Network admins troubleshooting routing issues

Complementary Tools:

Alternative Online Services

IPinfo.io - Developer-friendly with JSON API
IPAPI.com - Free tier, currency and language detection
ip-api.com - Batch lookup support (100 IPs per request)
iplocation.net - Historical IP data and change tracking

Command-Line IP Lookup (Linux/Mac/Windows)

Using whois Command

# Basic WHOIS lookup for IP ownership
whois 8.8.8.8

# Output includes:
# Organization: Google LLC (GOGL)
# NetRange: 8.8.8.0 - 8.8.8.255
# CIDR: 8.8.8.0/24
# NetName: LVLT-GOGL-8-8-8
# Country: US
# RegDate: 2014-03-14
# OrgAbuseHandle: ABUSE5250-ARIN
# OrgAbuse Email: network-abuse@google.com

Install WHOIS:

# Ubuntu/Debian
sudo apt-get install whois

# macOS (via Homebrew)
brew install whois

# Windows (via WSL or download from jwhois)

Useful WHOIS Flags:

# Query specific RIR
whois -h whois.ripe.net 203.0.113.42

# Get ASN details
whois -h whois.cymru.com " -v 8.8.8.8"
# Returns: AS15169 | 8.8.8.0/24 | US | arin | 2014-03-14 | GOOGLE - Google LLC

Using geoiplookup (MaxMind CLI Tool)

# Install GeoIP command-line tools
sudo apt-get install geoip-bin geoip-database

# Lookup country
geoiplookup 8.8.8.8
# Output: GeoIP Country Edition: US, United States

# Lookup city (requires GeoLite2-City database)
geoiplookup 8.8.8.8
# Output: GeoIP City Edition, Rev 1: US, CA, California, Mountain View, 94043

Using nslookup and dig for Reverse DNS

# Reverse DNS lookup (PTR record)
nslookup 8.8.8.8
# Returns: 8.8.8.8.in-addr.arpa name = dns.google.

# Alternative with dig
dig -x 8.8.8.8 +short
# Returns: dns.google.

# Batch reverse DNS for subnet
for ip in 8.8.8.{1..10}; do
  echo -n "$ip: "
  dig -x $ip +short
done

Using curl with IP Geolocation APIs

# ipinfo.io API
curl ipinfo.io/8.8.8.8
# Returns JSON:
# {
#   "ip": "8.8.8.8",
#   "hostname": "dns.google",
#   "city": "Mountain View",
#   "region": "California",
#   "country": "US",
#   "loc": "37.4056,-122.0775",
#   "org": "AS15169 Google LLC"
# }

# ip-api.com (no auth required)
curl "http://ip-api.com/json/8.8.8.8?fields=status,message,country,city,isp,as,proxy"

# Parse with jq
curl -s ipinfo.io/8.8.8.8 | jq -r '.city, .country'

Programmatic IP Lookup (APIs and SDKs)

Python Implementation

import requests
import geoip2.database

# Method 1: Using MaxMind GeoLite2 database (offline, fast)
def lookup_ip_offline(ip_address):
    """Lookup IP using local MaxMind database"""
    reader = geoip2.database.Reader('/path/to/GeoLite2-City.mmdb')

    try:
        response = reader.city(ip_address)
        return {
            'ip': ip_address,
            'country': response.country.name,
            'country_code': response.country.iso_code,
            'city': response.city.name,
            'latitude': response.location.latitude,
            'longitude': response.location.longitude,
            'timezone': response.location.time_zone,
            'postal_code': response.postal.code,
            'accuracy_radius': response.location.accuracy_radius
        }
    except geoip2.errors.AddressNotFoundError:
        return {'error': 'IP address not found in database'}
    finally:
        reader.close()

# Method 2: Using IPinfo.io API (online, requires token)
def lookup_ip_online(ip_address, token='YOUR_API_TOKEN'):
    """Lookup IP using IPinfo.io API"""
    url = f"https://ipinfo.io/{ip_address}/json"
    headers = {'Authorization': f'Bearer {token}'}

    response = requests.get(url, headers=headers)

    if response.status_code == 200:
        data = response.json()
        return {
            'ip': data.get('ip'),
            'hostname': data.get('hostname'),
            'city': data.get('city'),
            'region': data.get('region'),
            'country': data.get('country'),
            'location': data.get('loc'),  # "lat,long" format
            'org': data.get('org'),  # ASN + Organization
            'postal': data.get('postal'),
            'timezone': data.get('timezone')
        }
    else:
        return {'error': f'API request failed: {response.status_code}'}

# Method 3: Batch lookup for fraud detection
def check_fraud_risk(ip_address, billing_country):
    """Check if IP location matches billing country"""
    ip_data = lookup_ip_offline(ip_address)

    if ip_data.get('country_code') != billing_country:
        return {
            'risk_level': 'HIGH',
            'reason': f"IP country ({ip_data.get('country')}) doesn't match billing ({billing_country})",
            'recommendation': 'Flag for manual review'
        }
    elif ip_data.get('accuracy_radius', 0) > 100:
        return {
            'risk_level': 'MEDIUM',
            'reason': f"Location accuracy low ({ip_data.get('accuracy_radius')}km radius)",
            'recommendation': 'Request additional verification'
        }
    else:
        return {
            'risk_level': 'LOW',
            'reason': 'IP location matches billing country',
            'recommendation': 'Proceed with order'
        }

# Usage examples
result = lookup_ip_offline('203.0.113.42')
print(f"City: {result['city']}, Country: {result['country']}")

fraud_check = check_fraud_risk('203.0.113.42', 'US')
print(f"Fraud Risk: {fraud_check['risk_level']} - {fraud_check['reason']}")

Node.js Implementation

const geoip = require('geoip-lite');
const axios = require('axios');

// Method 1: Using geoip-lite (offline, lightweight)
function lookupIPOffline(ipAddress) {
    const geo = geoip.lookup(ipAddress);

    if (!geo) {
        return { error: 'IP address not found' };
    }

    return {
        ip: ipAddress,
        country: geo.country,
        region: geo.region,
        city: geo.city,
        latitude: geo.ll[0],
        longitude: geo.ll[1],
        timezone: geo.timezone,
        range: geo.range,
        accuracy: 'Country: High, City: Medium'
    };
}

// Method 2: Using ipinfo.io API
async function lookupIPOnline(ipAddress, token = 'YOUR_API_TOKEN') {
    try {
        const response = await axios.get(`https://ipinfo.io/${ipAddress}/json`, {
            headers: { 'Authorization': `Bearer ${token}` }
        });

        const data = response.data;
        const [lat, lon] = data.loc ? data.loc.split(',') : [null, null];

        return {
            ip: data.ip,
            hostname: data.hostname,
            city: data.city,
            region: data.region,
            country: data.country,
            latitude: parseFloat(lat),
            longitude: parseFloat(lon),
            org: data.org,
            postal: data.postal,
            timezone: data.timezone
        };
    } catch (error) {
        return { error: `API request failed: ${error.message}` };
    }
}

// Method 3: VPN/Proxy detection
async function detectVPN(ipAddress) {
    const geo = lookupIPOffline(ipAddress);

    // Heuristic checks
    const suspiciousASNs = [
        'AS14061', // DigitalOcean
        'AS16509', // Amazon AWS
        'AS15169', // Google Cloud
        // Add known VPN ASNs
    ];

    // Check if IP belongs to datacenter
    const isDatacenter = suspiciousASNs.some(asn =>
        geo.org && geo.org.includes(asn)
    );

    return {
        ip: ipAddress,
        isVPN: isDatacenter,
        risk: isDatacenter ? 'HIGH' : 'LOW',
        reason: isDatacenter ? 'IP belongs to datacenter/cloud provider' : 'Residential ISP'
    };
}

// Usage
const result = lookupIPOffline('8.8.8.8');
console.log(`Location: ${result.city}, ${result.country}`);

lookupIPOnline('8.8.8.8').then(data => {
    console.log(`ISP: ${data.org}`);
});

detectVPN('203.0.113.42').then(vpn => {
    console.log(`VPN Risk: ${vpn.risk} - ${vpn.reason}`);
});

PHP Implementation (WordPress/Laravel)

<?php
// Using GeoIP2 PHP library
require_once 'vendor/autoload.php';

use GeoIp2\Database\Reader;

function lookupIP($ipAddress) {
    $reader = new Reader('/path/to/GeoLite2-City.mmdb');

    try {
        $record = $reader->city($ipAddress);

        return [
            'ip' => $ipAddress,
            'country' => $record->country->name,
            'country_code' => $record->country->isoCode,
            'city' => $record->city->name,
            'postal_code' => $record->postal->code,
            'latitude' => $record->location->latitude,
            'longitude' => $record->location->longitude,
            'timezone' => $record->location->timeZone,
            'accuracy_radius' => $record->location->accuracyRadius
        ];
    } catch (\GeoIp2\Exception\AddressNotFoundException $e) {
        return ['error' => 'IP not found'];
    } finally {
        $reader->close();
    }
}

// Get visitor's IP from request
function getVisitorIP() {
    // Check for proxy headers
    if (!empty($_SERVER['HTTP_CF_CONNECTING_IP'])) {
        // Cloudflare
        return $_SERVER['HTTP_CF_CONNECTING_IP'];
    } elseif (!empty($_SERVER['HTTP_X_FORWARDED_FOR'])) {
        // Load balancer
        $ips = explode(',', $_SERVER['HTTP_X_FORWARDED_FOR']);
        return trim($ips[0]);
    } else {
        return $_SERVER['REMOTE_ADDR'];
    }
}

// Fraud detection example
function checkFraudRisk($ipAddress, $billingCountry) {
    $ipData = lookupIP($ipAddress);

    if (isset($ipData['error'])) {
        return [
            'risk' => 'UNKNOWN',
            'message' => 'Could not verify IP location'
        ];
    }

    if ($ipData['country_code'] !== $billingCountry) {
        return [
            'risk' => 'HIGH',
            'message' => sprintf(
                'IP country (%s) does not match billing country (%s)',
                $ipData['country'],
                $billingCountry
            ),
            'action' => 'REVIEW_MANUALLY'
        ];
    }

    if ($ipData['accuracy_radius'] > 100) {
        return [
            'risk' => 'MEDIUM',
            'message' => 'Location accuracy is low',
            'action' => 'REQUEST_VERIFICATION'
        ];
    }

    return [
        'risk' => 'LOW',
        'message' => 'IP location verified',
        'action' => 'PROCEED'
    ];
}

// Usage
$visitorIP = getVisitorIP();
$location = lookupIP($visitorIP);
echo "Visitor from: {$location['city']}, {$location['country']}<br>";

$fraud = checkFraudRisk($visitorIP, 'US');
echo "Fraud Risk: {$fraud['risk']} - {$fraud['message']}";
?>

API Rate Limits and Costs:

  • Free Tier (IPinfo.io): 50,000 requests/month
  • MaxMind GeoIP2 Precision: $0.005 per query (500/month minimum)
  • IP2Location Web Service: $8/month for 10,000 queries
  • ipapi.com: 1,000 requests/month free, $10/month for 10,000

For high-volume applications, download local databases (updated monthly/weekly) to avoid API costs and latency.

VPN and Proxy Detection (Advanced Security)

VPN and proxy detection is critical for content licensing, fraud prevention, and security monitoring. Users employ these technologies to mask their true location, circumvent geographic restrictions, or hide malicious activity.

Why Detect VPNs and Proxies?

Legitimate Use Cases:

  • Content Licensing: Streaming services enforce regional rights (Netflix, Hulu, BBC iPlayer)
  • Fraud Prevention: E-commerce blocks orders with location mismatches
  • Security Monitoring: Corporate networks detect shadow IT and data exfiltration
  • Compliance: GDPR/CCPA require accurate user location for data residency
  • Gaming: Prevent region-hopping for cheaper game purchases

Attack Scenarios VPNs/Proxies Enable:

  • Credential Stuffing: Attackers rotate IPs to bypass rate limiting
  • Web Scraping: Bots use residential proxy networks to evade blocking
  • Click Fraud: Ad fraud rings use proxies to generate fake traffic
  • Account Takeover: Hackers use VPNs to match victim’s region after phishing

VPN Detection Methods

1. Database Matching (95% Accuracy)

How It Works: Maintain databases of known VPN/proxy IP ranges based on:

  • Commercial VPN Providers: NordVPN, ExpressVPN, Surfshark announce their server IPs
  • Datacenter Ranges: AWS, DigitalOcean, Vultr (commonly used for VPN endpoints)
  • Proxy Lists: Public and leaked proxy server lists
  • Crowdsourced Reports: User submissions of detected VPN IPs

Implementation:

import requests

def detect_vpn_database(ip_address, api_key='YOUR_KEY'):
    """Check if IP is a known VPN using IPQualityScore API"""
    url = f"https://www.ipqualityscore.com/api/json/ip/{api_key}/{ip_address}"
    params = {
        'strictness': 1,  # 0=lenient, 1=moderate, 2=strict
        'allow_public_access_points': 'false'
    }

    response = requests.get(url, params=params)
    data = response.json()

    return {
        'is_vpn': data.get('vpn', False),
        'is_proxy': data.get('proxy', False),
        'is_tor': data.get('tor', False),
        'fraud_score': data.get('fraud_score', 0),  # 0-100 scale
        'connection_type': data.get('connection_type'),  # Premium/Residential/Corporate
        'recent_abuse': data.get('recent_abuse', False),
        'bot_status': data.get('bot_status', False)
    }

# Usage
result = detect_vpn_database('203.0.113.42')
if result['is_vpn'] or result['fraud_score'] > 75:
    print("VPN or high-risk IP detected")

Top VPN Detection APIs:

  • IPQualityScore - 99.9% accuracy, fraud scoring, $25/month for 5,000 queries
  • IPHub - 500 free checks/day, $5/month for 10,000
  • MaxMind GeoIP2 Anonymous IP - $100/month subscription, includes Tor detection
  • IPQS Proxy Detection - Real-time threat feeds

2. ASN (Autonomous System Number) Analysis

How It Works: VPN providers typically operate from datacenter ASNs, while residential users connect through ISP ASNs.

Detection Logic:

import geoip2.database

def detect_vpn_asn(ip_address):
    """Detect VPN based on ASN classification"""
    reader = geoip2.database.Reader('/path/to/GeoLite2-ASN.mmdb')

    try:
        response = reader.asn(ip_address)
        asn = response.autonomous_system_number
        org = response.autonomous_system_organization

        # Known datacenter ASNs
        datacenter_asns = {
            16509: 'Amazon AWS',
            15169: 'Google Cloud',
            14061: 'DigitalOcean',
            8075: 'Microsoft Azure',
            20473: 'Choopa (Vultr)',
            63949: 'Linode',
            24940: 'Hetzner Online',
            # Add more datacenter/VPN ASNs
        }

        is_datacenter = asn in datacenter_asns

        # Check organization name for VPN keywords
        vpn_keywords = ['vpn', 'proxy', 'anonymizer', 'privacy', 'tunnel']
        has_vpn_keyword = any(kw in org.lower() for kw in vpn_keywords)

        return {
            'asn': asn,
            'organization': org,
            'is_datacenter': is_datacenter,
            'likely_vpn': is_datacenter or has_vpn_keyword,
            'datacenter_name': datacenter_asns.get(asn, 'Unknown')
        }
    except Exception as e:
        return {'error': str(e)}
    finally:
        reader.close()

# Usage
result = detect_vpn_asn('203.0.113.42')
if result['likely_vpn']:
    print(f"Likely VPN: {result['organization']} (ASN{result['asn']})")

Datacenter ASN Indicators:

  • AS16509 - Amazon AWS
  • AS15169 - Google Cloud Platform
  • AS14061 - DigitalOcean
  • AS8075 - Microsoft Azure
  • AS13335 - Cloudflare (also CDN)
  • AS20473 - Choopa/Vultr

Residential ISP ASNs (Not VPNs):

  • AS7922 - Comcast Cable
  • AS7018 - AT&T Services
  • AS22773 - Cox Communications
  • AS11351 - Charter Communications (Spectrum)

3. WebRTC Leak Detection (Client-Side)

How It Works: WebRTC (Web Real-Time Communication) can reveal user’s true local IP address even when using a VPN, because browsers establish peer-to-peer connections that bypass VPN tunnels.

JavaScript Implementation:

// Detect VPN via WebRTC leak
async function detectWebRTCLeak() {
    return new Promise((resolve) => {
        const localIPs = [];
        const vpnIPs = [];

        // Create RTCPeerConnection
        const pc = new RTCPeerConnection({
            iceServers: [{urls: 'stun:stun.l.google.com:19302'}]
        });

        // Create dummy data channel
        pc.createDataChannel('');

        // Create offer to trigger ICE candidate gathering
        pc.createOffer().then(offer => pc.setLocalDescription(offer));

        // Listen for ICE candidates (discovered IPs)
        pc.onicecandidate = (ice) => {
            if (!ice || !ice.candidate || !ice.candidate.candidate) return;

            const ipRegex = /([0-9]{1,3}\.){3}[0-9]{1,3}/;
            const match = ipRegex.exec(ice.candidate.candidate);

            if (match) {
                const ip = match[0];

                // Classify IP
                if (ip.startsWith('192.168.') || ip.startsWith('10.') ||
                    ip.startsWith('172.')) {
                    localIPs.push(ip);  // Private/local IP
                } else {
                    vpnIPs.push(ip);  // Public IP (might be VPN)
                }
            }
        };

        // Wait for ICE gathering to complete
        setTimeout(() => {
            pc.close();

            resolve({
                localIPs: [...new Set(localIPs)],
                vpnIPs: [...new Set(vpnIPs)],
                leakDetected: localIPs.length > 0,
                vpnSuspected: vpnIPs.length > 1  // Multiple public IPs = VPN rotation
            });
        }, 2000);
    });
}

// Usage
detectWebRTCLeak().then(result => {
    console.log('WebRTC IPs:', result);

    if (result.leakDetected) {
        console.log('VPN leak detected - true IP:', result.localIPs[0]);

        // Send to server for comparison with HTTP IP
        fetch('/api/check-vpn', {
            method: 'POST',
            headers: {'Content-Type': 'application/json'},
            body: JSON.stringify({
                httpIP: window.location.host,  // IP from HTTP request
                webrtcIPs: result.vpnIPs
            })
        });
    }
});

VPN Leak Indicators:

  • Multiple Public IPs: VPN service rotating endpoints
  • IP Mismatch: WebRTC IP differs from HTTP request IP
  • Local IP Visibility: Should be hidden if VPN configured correctly

Browser Support: Chrome, Firefox, Safari, Edge (95%+ coverage)

4. DNS Leak Detection

How It Works: VPN tunnels route traffic through VPN servers, but DNS queries might leak through ISP’s DNS servers, revealing true location.

Detection Method:

# Check DNS servers visible to client
# Client-side JavaScript
fetch('https://dns-leak-test-api.com/check')
  .then(res => res.json())
  .then(data => {
    console.log('DNS Servers:', data.dns_servers);

    // If DNS servers belong to local ISP, VPN has DNS leak
    const isLeak = data.dns_servers.some(server =>
      server.country !== data.vpn_country
    );

    if (isLeak) {
      console.log('DNS leak detected');
    }
  });

DNS Leak Test Services:

  • dnsleaktest.com - Public API for DNS server detection
  • ipleak.net - Comprehensive leak testing (WebRTC, DNS, IPv6)
  • browserleaks.com - Full browser fingerprinting suite

5. Latency and Timing Analysis

How It Works: VPN connections add 20-200ms latency due to encryption overhead and routing through distant servers. Analyzing round-trip times can reveal VPN usage.

Detection Algorithm:

import subprocess
import statistics

def detect_vpn_latency(ip_address):
    """Detect VPN based on abnormal latency"""
    # Ping IP address 10 times
    pings = []
    for _ in range(10):
        result = subprocess.run(
            ['ping', '-c', '1', '-W', '2', ip_address],
            capture_output=True,
            text=True
        )

        if result.returncode == 0:
            # Extract latency from ping output
            # Example: "time=42.3 ms"
            time_line = [line for line in result.stdout.split('\n') if 'time=' in line]
            if time_line:
                latency = float(time_line[0].split('time=')[1].split(' ')[0])
                pings.append(latency)

    if not pings:
        return {'error': 'Host unreachable'}

    avg_latency = statistics.mean(pings)
    std_dev = statistics.stdev(pings) if len(pings) > 1 else 0

    # Heuristic thresholds
    is_vpn_suspected = (
        avg_latency > 100 or  # High latency suggests VPN/proxy
        std_dev > 50  # High variance suggests congested VPN server
    )

    return {
        'average_latency_ms': round(avg_latency, 2),
        'std_deviation': round(std_dev, 2),
        'min_latency': min(pings),
        'max_latency': max(pings),
        'vpn_suspected': is_vpn_suspected,
        'reason': 'High latency/variance' if is_vpn_suspected else 'Normal latency'
    }

# Usage
result = detect_vpn_latency('203.0.113.42')
print(f"Latency: {result['average_latency_ms']}ms - VPN: {result['vpn_suspected']}")

Latency Benchmarks:

  • Direct Connection (Residential): 10-50ms within country, 50-150ms international
  • VPN Connection: 50-200ms overhead depending on encryption and server distance
  • Proxy Connection: 100-500ms (free proxies), 20-100ms (premium residential proxies)
  • Tor Network: 300-1000ms due to 3-hop circuit

6. Behavioral Fingerprinting

How It Works: Combine multiple signals for probabilistic VPN detection:

  • Browser fingerprint consistency: Canvas, WebGL, fonts, plugins
  • Time zone mismatch: IP location vs browser Intl.DateTimeFormat().resolvedOptions().timeZone
  • Language mismatch: IP country vs Accept-Language header
  • Screen resolution patterns: Common VPS configurations (1024×768 suggests VM)
  • Connection history: IP changes frequently = VPN hopping

Implementation:

async function comprehensiveVPNDetection() {
    const signals = {
        ip: await fetch('/api/my-ip').then(r => r.json()),
        timezone: Intl.DateTimeFormat().resolvedOptions().timeZone,
        language: navigator.language,
        screen: `${screen.width}x${screen.height}`,
        webrtc: await detectWebRTCLeak(),
        plugins: Array.from(navigator.plugins).map(p => p.name)
    };

    // Check for mismatches
    const suspiciousSignals = [];

    // Timezone mismatch
    const timezoneCountry = getCountryFromTimezone(signals.timezone);
    if (timezoneCountry !== signals.ip.country) {
        suspiciousSignals.push('Timezone mismatch');
    }

    // Language mismatch
    const languageCountry = signals.language.split('-')[1];
    if (languageCountry && languageCountry !== signals.ip.country) {
        suspiciousSignals.push('Language mismatch');
    }

    // WebRTC leak
    if (signals.webrtc.leakDetected) {
        suspiciousSignals.push('WebRTC leak');
    }

    // Common VPS screen resolution
    const vpsResolutions = ['1024x768', '1366x768', '1920x1080'];
    if (vpsResolutions.includes(signals.screen)) {
        suspiciousSignals.push('VPS-like resolution');
    }

    return {
        signals: signals,
        suspiciousSignals: suspiciousSignals,
        vpnProbability: suspiciousSignals.length * 0.25,  // 0-1 scale
        recommendation: suspiciousSignals.length >= 2 ? 'BLOCK' : 'ALLOW'
    };
}

Accuracy Trade-offs:

  • False Positives: Corporate VPN users, travelers, privacy-conscious users
  • False Negatives: Residential proxy networks, sophisticated obfuscation
  • Recommendation: Use multi-signal approach with threshold tuning for your use case

Related Tools:

IP Address Security and Threat Intelligence

IP addresses are critical indicators of compromise (IOCs) in cybersecurity. Threat intelligence platforms track malicious IPs associated with DDoS attacks, malware distribution, phishing campaigns, and botnet command-and-control servers.

Common IP-Based Threats

1. DDoS (Distributed Denial of Service) Attacks

Attack Pattern: Thousands of compromised devices (botnet) flood your server with requests

Detection Signals:

  • High request rate from single IP (>100 req/sec)
  • Geographic clustering (botnet from single country/ASN)
  • Unusual user agents (scrapers, bots, headless browsers)
  • Syn flood (TCP handshake never completes)

Mitigation with IP Intelligence:

import redis
from collections import defaultdict

# Track request counts in Redis
def detect_ddos(ip_address, redis_client):
    """Track IP request rates for DDoS detection"""
    key = f"rate_limit:{ip_address}"

    # Increment request counter
    count = redis_client.incr(key)

    # Set 60-second expiry if first request
    if count == 1:
        redis_client.expire(key, 60)

    # Check thresholds
    if count > 100:  # 100 requests per minute
        return {
            'action': 'BLOCK',
            'reason': 'DDoS suspected - excessive request rate',
            'requests_per_minute': count
        }
    elif count > 50:
        return {
            'action': 'CHALLENGE',  # CAPTCHA
            'reason': 'High request rate - verify human',
            'requests_per_minute': count
        }
    else:
        return {'action': 'ALLOW', 'requests_per_minute': count}

# Usage with Flask
from flask import request

@app.before_request
def ddos_protection():
    visitor_ip = request.remote_addr
    ddos_check = detect_ddos(visitor_ip, redis_client)

    if ddos_check['action'] == 'BLOCK':
        abort(429, description='Too many requests')

DDoS Protection Services:

  • Cloudflare - Free tier includes DDoS mitigation
  • AWS Shield Standard - Automatic protection for AWS resources
  • Google Cloud Armor - Adaptive protection with rate limiting

2. Credential Stuffing and Brute Force

Attack Pattern: Attackers use stolen username/password pairs to gain unauthorized access

Detection Logic:

def detect_credential_stuffing(ip_address, failed_logins):
    """Detect brute force based on failed login attempts"""
    # Get login history
    history = redis_client.lrange(f"login_attempts:{ip_address}", 0, -1)

    threshold = 5  # 5 failed attempts = lock
    window = 300  # 5 minutes

    recent_failures = [
        timestamp for timestamp in history
        if time.time() - float(timestamp) < window
    ]

    if len(recent_failures) >= threshold:
        return {
            'action': 'LOCKOUT',
            'duration_seconds': 1800,  # 30 minute lockout
            'failed_attempts': len(recent_failures),
            'recommendation': 'Implement MFA for this user'
        }
    elif len(recent_failures) >= 3:
        return {
            'action': 'DELAY',
            'delay_seconds': 5,  # Progressive delay
            'failed_attempts': len(recent_failures)
        }
    else:
        return {'action': 'ALLOW'}

Advanced Detection:

  • Velocity checking: Multiple login attempts across different usernames
  • Device fingerprinting: New device + wrong password = suspicious
  • Geolocation anomalies: Login from impossible travel distance
  • ASN blacklisting: Block datacenter IPs from login pages

3. Web Scraping and Content Theft

Attack Pattern: Bots systematically crawl your site to steal content, pricing, or data

Detection Techniques:

def detect_web_scraper(ip_address, user_agent, request_pattern):
    """Identify web scraping bots"""
    suspicious_signals = []

    # Check user agent
    bot_keywords = ['bot', 'crawler', 'scraper', 'spider', 'curl', 'wget', 'python']
    if any(keyword in user_agent.lower() for keyword in bot_keywords):
        suspicious_signals.append('Bot user agent')

    # Check request pattern
    if request_pattern.get('pages_per_minute', 0) > 20:
        suspicious_signals.append('Excessive page requests')

    if request_pattern.get('follows_robots_txt', False) == False:
        suspicious_signals.append('Ignores robots.txt')

    # Check if datacenter IP
    asn_data = detect_vpn_asn(ip_address)
    if asn_data.get('is_datacenter'):
        suspicious_signals.append('Datacenter IP')

    # Check JavaScript execution
    if not request_pattern.get('javascript_enabled'):
        suspicious_signals.append('No JavaScript (headless browser)')

    scraper_score = len(suspicious_signals) * 25  # 0-100 scale

    return {
        'is_scraper': scraper_score >= 50,
        'confidence': scraper_score,
        'signals': suspicious_signals,
        'recommendation': 'BLOCK' if scraper_score >= 75 else 'CHALLENGE'
    }

Anti-Scraping Measures:

  • Rate limiting per IP and per user agent
  • Honeypot links invisible to humans, followed by bots
  • CAPTCHA challenges on suspicious behavior
  • IP reputation checking with threat intelligence feeds

4. Threat Intelligence Feeds

Top Threat Intel Sources:

Spamhaus Block List (SBL)
URL: https://www.spamhaus.org/sbl/
What It Tracks: Spam sources, malware distribution, phishing sites
Query Method: DNS-based blackhole list (DNSBL)

# Check if IP is listed in Spamhaus
host 42.113.0.203.zen.spamhaus.org

# If listed, returns:
# 42.113.0.203.zen.spamhaus.org has address 127.0.0.2
# Return codes: 127.0.0.2 = SBL, 127.0.0.3 = XBL, etc.

AbuseIPDB
URL: https://www.abuseipdb.com/
What It Tracks: Crowdsourced abuse reports (DDoS, hacking, spam)
API Example:

import requests

def check_abuse_ipdb(ip_address, api_key='YOUR_KEY'):
    """Query AbuseIPDB for IP reputation"""
    url = 'https://api.abuseipdb.com/api/v2/check'
    headers = {
        'Key': api_key,
        'Accept': 'application/json'
    }
    params = {
        'ipAddress': ip_address,
        'maxAgeInDays': 90,  # Reports within last 90 days
        'verbose': True
    }

    response = requests.get(url, headers=headers, params=params)
    data = response.json()['data']

    return {
        'ip': data['ipAddress'],
        'abuse_confidence_score': data['abuseConfidenceScore'],  # 0-100
        'total_reports': data['totalReports'],
        'num_distinct_users': data['numDistinctUsers'],
        'last_reported_at': data['lastReportedAt'],
        'is_whitelisted': data['isWhitelisted'],
        'usage_type': data['usageType'],  # Commercial, ISP, Hosting, etc.
        'country': data['countryCode'],
        'threat_level': 'HIGH' if data['abuseConfidenceScore'] > 75 else 'LOW'
    }

# Usage
result = check_abuse_ipdb('203.0.113.42')
if result['abuse_confidence_score'] > 50:
    print(f"High abuse risk: {result['total_reports']} reports")

AlienVault OTX (Open Threat Exchange)
URL: https://otx.alienvault.com/
What It Tracks: Malware C2 servers, exploit kits, APT indicators
Free Tier: 10,000 API requests/month

Talos Intelligence (Cisco)
URL: https://talosintelligence.com/
What It Tracks: Reputation scoring, malware hosting, email spam
Reputation Lookup: Web interface and API

5. Implementing IP Reputation Scoring

def calculate_ip_reputation(ip_address):
    """Aggregate multiple threat intelligence sources"""
    scores = {
        'abuseipdb': 0,
        'spamhaus': 0,
        'vpn_detection': 0,
        'geoip_risk': 0
    }

    # Check AbuseIPDB
    abuse_data = check_abuse_ipdb(ip_address)
    scores['abuseipdb'] = abuse_data['abuse_confidence_score']

    # Check Spamhaus
    spamhaus_listed = check_spamhaus_dnsbl(ip_address)
    scores['spamhaus'] = 100 if spamhaus_listed else 0

    # Check VPN/Proxy
    vpn_data = detect_vpn_database(ip_address)
    if vpn_data['is_vpn']:
        scores['vpn_detection'] = 50  # VPN = moderate risk
    if vpn_data['is_proxy']:
        scores['vpn_detection'] = 75  # Proxy = higher risk
    if vpn_data['is_tor']:
        scores['vpn_detection'] = 90  # Tor = very high risk

    # Check high-risk countries (adjust based on your risk model)
    geoip = lookup_ip_offline(ip_address)
    high_risk_countries = ['CN', 'RU', 'KP', 'IR']  # Example
    if geoip['country_code'] in high_risk_countries:
        scores['geoip_risk'] = 40

    # Calculate weighted average
    total_score = (
        scores['abuseipdb'] * 0.4 +  # 40% weight
        scores['spamhaus'] * 0.3 +    # 30% weight
        scores['vpn_detection'] * 0.2 +  # 20% weight
        scores['geoip_risk'] * 0.1    # 10% weight
    )

    return {
        'ip': ip_address,
        'reputation_score': round(total_score, 2),
        'threat_level': get_threat_level(total_score),
        'component_scores': scores,
        'recommendation': get_action_recommendation(total_score)
    }

def get_threat_level(score):
    if score >= 75:
        return 'CRITICAL'
    elif score >= 50:
        return 'HIGH'
    elif score >= 25:
        return 'MEDIUM'
    else:
        return 'LOW'

def get_action_recommendation(score):
    if score >= 75:
        return 'BLOCK'
    elif score >= 50:
        return 'CHALLENGE'  # CAPTCHA or rate limit
    elif score >= 25:
        return 'MONITOR'
    else:
        return 'ALLOW'

# Usage in production
visitor_ip = get_visitor_ip()
reputation = calculate_ip_reputation(visitor_ip)

if reputation['threat_level'] in ['CRITICAL', 'HIGH']:
    log_security_event(visitor_ip, reputation)
    if reputation['recommendation'] == 'BLOCK':
        return error_response(403, 'Access denied')

Integration with WAF (Web Application Firewall):

# Nginx with ngx_http_geoip2_module
http {
    geoip2 /path/to/GeoLite2-Country.mmdb {
        $geoip2_country_code country iso_code;
    }

    # Block high-risk countries
    map $geoip2_country_code $blocked_country {
        default 0;
        CN 1;  # China
        RU 1;  # Russia
        KP 1;  # North Korea
    }

    server {
        location / {
            if ($blocked_country) {
                return 403 "Access denied from your country";
            }
            proxy_pass http://backend;
        }
    }
}

Related Security Tools:

IP addresses constitute personal data under GDPR Article 4(1) when they can identify an individual—even indirectly. Organizations processing IP addresses must comply with strict regulatory requirements.

Is an IP Address Personal Data?

GDPR Definition (Article 4(1)):

“Personal data” means any information relating to an identified or identifiable natural person (data subject).

Court Rulings:

  • Case C-582/14 (Patrick Breyer v Germany, 2016): ECJ ruled dynamic IP addresses are personal data when ISP can link them to individuals
  • Static IPs: Always personal data (permanently assigned to individual/household)
  • Dynamic IPs: Personal data when combined with ISP logs linking IP to customer

CCPA (California Consumer Privacy Act):
IP addresses are “personal information” under CCPA §1798.140(o)(1)(A)—“identifies, relates to, describes, or is reasonably capable of being associated with” a particular consumer.

GDPR Article 6 - Lawful Bases:

1. Legitimate Interest (Most Common)

Use Cases:

  • Security monitoring: Detecting DDoS, fraud, malware
  • Network operations: Load balancing, traffic routing
  • Analytics: Aggregate statistics (with anonymization)

Requirements:

  • Necessity test: Processing must be necessary for legitimate interest
  • Balancing test: Your interests don’t override user rights
  • Transparency: Privacy policy explains IP logging
  • Data minimization: Collect only necessary IP data

Example Privacy Policy Language:

“We collect IP addresses to prevent fraud, protect against DDoS attacks, and troubleshoot technical issues. IPs are stored for 90 days in server logs, then automatically deleted. This processing is based on legitimate interest (GDPR Art. 6(1)(f)) for security and technical operation of our services.”

2. Contract Performance (E-commerce)

Use Cases:

  • Order fulfillment: Detecting shipping address fraud
  • Payment processing: Verifying transaction legitimacy
  • Service delivery: Content delivery based on location

Requirements: IP processing must be strictly necessary for contract execution

Use Cases:

  • Law enforcement requests: Court orders, subpoenas
  • Tax compliance: VAT location verification
  • Copyright enforcement: DMCA takedown notices

Use Cases:

  • Marketing: Geo-targeted advertising
  • Personalization: Location-based recommendations

Requirements:

  • Explicit opt-in: Pre-checked boxes insufficient
  • Granular: Separate consent for different purposes
  • Revocable: Easy opt-out mechanism

Data Retention Limits

Industry Standards:

  • Web server logs: 30-90 days maximum
  • Security incident logs: 12 months (regulatory requirements)
  • Analytics data: Anonymize after 14 days (Google Analytics default)
  • Fraud detection: 6-12 months for pattern analysis

Automated Deletion Example:

import datetime
from sqlalchemy import func

def delete_old_ip_logs():
    """GDPR-compliant IP log deletion"""
    # Delete logs older than 90 days
    cutoff_date = datetime.datetime.now() - datetime.timedelta(days=90)

    deleted_count = db.session.query(AccessLog).\
        filter(AccessLog.timestamp < cutoff_date).\
        delete(synchronize_session='fetch')

    db.session.commit()

    log.info(f"Deleted {deleted_count} IP log entries older than 90 days")

    return deleted_count

# Schedule with cron
# 0 2 * * * /usr/bin/python3 /opt/scripts/delete_ip_logs.py

IP Address Anonymization Techniques

1. IP Masking (Pseudonymization)

IPv4 Masking: Zero out last octet
203.0.113.42 → 203.0.113.0

IPv6 Masking: Zero out last 80 bits
2001:db8:85a3::8a2e:370:7334 → 2001:db8:85a3::

Python Implementation:

import ipaddress

def anonymize_ipv4(ip_address):
    """Mask last octet of IPv4 address"""
    ip = ipaddress.IPv4Address(ip_address)
    network = ipaddress.IPv4Network(f"{ip}/24", strict=False)
    return str(network.network_address)

def anonymize_ipv6(ip_address):
    """Mask last 80 bits of IPv6 address"""
    ip = ipaddress.IPv6Address(ip_address)
    network = ipaddress.IPv6Network(f"{ip}/48", strict=False)
    return str(network.network_address)

# Usage
print(anonymize_ipv4("203.0.113.42"))  # 203.0.113.0
print(anonymize_ipv6("2001:db8:85a3::8a2e:370:7334"))  # 2001:db8:85a3::

Accuracy Trade-off: Preserves city-level geolocation, removes household identification

2. Hashing (One-Way Transformation)

import hashlib
import hmac

def hash_ip_with_salt(ip_address, secret_key):
    """Hash IP address with secret salt"""
    return hmac.new(
        secret_key.encode(),
        ip_address.encode(),
        hashlib.sha256
    ).hexdigest()

# Usage
secret = "your-secret-rotation-key"
hashed_ip = hash_ip_with_salt("203.0.113.42", secret)
print(hashed_ip)  # 7a3f5c8e9d2b1a4f6e8c0b3d5a7f9e1c...

# Store hashed IP instead of plaintext
# Allows rate limiting/abuse detection without storing real IPs

GDPR Status: Hashed IPs are still personal data if reversible with available key. Use for pseudonymization, not full anonymization.

3. Differential Privacy (Aggregate Analytics)

def add_laplace_noise(value, sensitivity, epsilon):
    """Add differential privacy noise to counts"""
    import numpy as np
    scale = sensitivity / epsilon
    noise = np.random.laplace(0, scale)
    return max(0, value + noise)  # Prevent negative counts

# Example: Country visitor counts with differential privacy
country_counts = {
    'US': 15000,
    'GB': 3500,
    'DE': 2800
}

epsilon = 0.1  # Privacy budget (lower = more privacy)
sensitivity = 1  # Each user affects count by ±1

noisy_counts = {
    country: int(add_laplace_noise(count, sensitivity, epsilon))
    for country, count in country_counts.items()
}

print("Original:", country_counts)
print("With DP noise:", noisy_counts)
# Output: Individual privacy protected, aggregate trends preserved

User Rights Under GDPR

Right to Access (Art. 15):
Users can request: “What IP addresses have you logged for me?”

Response Template:

{
  "data_subject": "user@example.com",
  "ip_addresses_logged": [
    {
      "ip": "203.0.113.42",
      "timestamp": "2025-12-01T14:23:45Z",
      "purpose": "Security monitoring",
      "retention_period": "90 days"
    }
  ],
  "legal_basis": "Legitimate interest (GDPR Art. 6(1)(f))",
  "third_party_sharing": "None"
}

Right to Erasure (Art. 17):
Delete IP logs upon request (unless legal obligation to retain)

Right to Object (Art. 21):
Allow users to opt-out of IP-based tracking (beyond security essentials)

Cross-Border Data Transfers

Problem: IP geolocation databases (MaxMind, IP2Location) often hosted in US

Solutions:

  • Standard Contractual Clauses (SCCs): EU-approved data transfer agreements
  • Adequacy Decisions: Transfer to countries with adequate protection (UK, Switzerland, Japan)
  • Data Localization: Use EU-hosted GeoIP databases (RIPE NCC)

Self-Hosting GeoIP Databases:

# Download MaxMind GeoLite2 (updates weekly)
wget https://download.maxmind.com/app/geoip_download?edition_id=GeoLite2-City&license_key=YOUR_KEY&suffix=tar.gz

# Extract to local server
tar -xzf GeoLite2-City.tar.gz

# Use with Python geoip2 library (no external API calls)
import geoip2.database
reader = geoip2.database.Reader('/opt/geoip/GeoLite2-City.mmdb')

Benefits: Full GDPR control, no third-party data sharing, low latency

Privacy-Focused Analytics:

  • Matomo - Self-hosted, GDPR-compliant analytics with IP anonymization
  • Plausible - Privacy-first analytics, no cookies, automatic IP anonymization
  • Fathom Analytics - Cookie-less, GDPR/CCPA compliant by design

Related Compliance Tools:

Frequently Asked Questions (IP Lookup FAQ)

Q1: How accurate is IP address geolocation?

Answer: Accuracy varies by geographic level and IP type:

Country-Level Accuracy: 95-99% reliable
IP allocation records from Regional Internet Registries (RIPE, ARIN, APNIC) provide highly accurate country attribution. Errors typically occur with:

  • VPN/proxy services showing datacenter country
  • Satellite/maritime internet showing gateway location
  • Recent IP block transfers between countries

City-Level Accuracy: 55-80% within 25-50km radius
MaxMind publishes accuracy metrics: 81% accuracy within 50km for US IPs, but only 66% for international IPs. Urban areas have higher accuracy than rural regions.

Factors Affecting Accuracy:

  • ISP reporting: Some ISPs don’t update geolocation databases
  • Mobile carriers: Users share IP addresses via CGNAT (gateway location shown)
  • IPv6 privacy extensions: Randomized interface IDs make tracking difficult
  • Database freshness: Weekly updates lag real-world changes

Postal Code Accuracy: Only 10-30% exact match
Postal code data is highly unreliable—use for rough estimates only, never for address validation.

Test Your IP’s Accuracy:
Use our What is My IP tool and compare the detected city with your actual location. If it shows your ISP’s regional office instead of your city, that’s normal geolocation behavior.

When to Trust IP Geolocation:

  • ✅ Currency selection on e-commerce sites
  • ✅ Content localization (language, pricing)
  • ✅ Regulatory compliance (GDPR cookie banners)
  • ❌ Precise delivery address verification
  • ❌ Legal evidence without additional correlation

Q2: Can IP lookup reveal my exact home address?

Answer: No—IP addresses map to approximate locations only, typically at city or ISP gateway level.

What IP Geolocation Actually Shows:

  • Country: Highly accurate (95%+)
  • State/Region: Moderately accurate
  • City: Often shows ISP’s regional office, not your home
  • Latitude/Longitude: Approximation with 25-50km accuracy radius
  • Postal Code: Unreliable, often represents city center

Why Street-Level Precision Is Impossible:

  • ISP DHCP pools: Residential IPs rotate through large blocks assigned to city/region
  • NAT (Network Address Translation): Hundreds of households share single public IP
  • CGNAT (Carrier-Grade NAT): Mobile/ISP users share IPs across entire regions

Privacy Protections:

  • ISPs don’t publish customer address mappings
  • GeoIP databases licensed for general location only
  • Legal protections prevent address disclosure without court order

What CAN Be Discovered:

  • ISP Name: Comcast, AT&T, Verizon, etc.
  • Network Owner: See WHOIS via our DNS Lookup tool
  • Organization: For business connections (static IPs)
  • General Location: “Los Angeles, California” not “123 Main Street”

Real Privacy Threats:

  • Browser fingerprinting: Canvas, WebGL, fonts reveal more than IP
  • WiFi geolocation: Mobile devices leak WiFi MAC addresses to Google/Apple
  • Cookies and tracking: Follow you across websites regardless of IP
  • Social engineering: Phishing attacks target individuals directly

Protecting Your Privacy:

  • Use VPN to mask true IP location (see VPN detection section)
  • Enable browser privacy protections (Firefox Enhanced Tracking Protection)
  • Use privacy-focused search engines (DuckDuckGo, Startpage)
  • Disable location services for websites

Q3: What’s the difference between static and dynamic IP addresses?

Answer: Static IPs remain permanent, dynamic IPs change periodically—each has distinct use cases and security implications.

Static IP Addresses

Definition: Permanently assigned to your device/account by ISP

Characteristics:

  • Never changes unless you request different IP or change ISP
  • Costs extra: $5-15/month residential, $25-100/month business
  • Direct reachability: Other devices can initiate connections to you
  • Easier to remember: Can use IP directly without DNS

Use Cases:

  • Web servers: Hosting websites requires consistent IP for DNS
  • Email servers: SMTP requires static IP for reputation
  • Remote access: VPN, SSH, RDP connections to home/office
  • Security cameras: Direct access without dynamic DNS
  • Gaming servers: Hosting multiplayer games
  • VoIP systems: Business phone systems

Security Implications:

  • Higher attack surface: Consistently targeted by port scanners
  • Permanent blacklisting: If IP gets on blocklist, difficult to remove
  • Privacy concerns: Activities permanently linked to single IP

Example Static IP Use:

# Web server with static IP
server {
    listen 203.0.113.42:80;
    server_name example.com www.example.com;
    # Configuration...
}

# DNS A record
example.com. 3600 IN A 203.0.113.42

Dynamic IP Addresses

Definition: Assigned temporarily from ISP’s IP pool, changes on router reboot or lease expiration

Characteristics:

  • Changes frequently: Every router reboot, or every 24 hours to 14 days
  • Standard for residential: Included in base internet plan
  • NAT required: Multiple devices share single public IP
  • Dynamic DNS needed: Domain names update automatically

Use Cases:

  • Residential users: Standard home internet
  • Mobile devices: Cellular data connections
  • Guest WiFi: Coffee shops, hotels, airports
  • Small businesses: Non-hosting internet usage

Security Implications:

  • Harder to track: IP changes make long-term tracking difficult
  • Ban circumvention: Reboot router to get new IP after ban
  • Lower attack risk: Constant IP rotation reduces persistent targeting

DHCP Lease Process:

1. DHCP Discover (Client → Server broadcast)
   "I need an IP address"

2. DHCP Offer (Server → Client)
   "You can use 192.168.1.105 for 24 hours"

3. DHCP Request (Client → Server)
   "I accept 192.168.1.105"

4. DHCP Acknowledge (Server → Client)
   "192.168.1.105 is yours until tomorrow 3:42 PM"

Checking Your IP Type:

# Check current IP
curl ipinfo.io

# Reboot router (or wait 24 hours)
# Check IP again
curl ipinfo.io

# If IP changed: Dynamic
# If IP same: Static (or very long DHCP lease)

Dynamic DNS Services:

  • No-IP - Free subdomain (yourname.ddns.net)
  • DuckDNS - Free, open-source
  • Dynu - Free with custom domain support
  • DynDNS (Oracle) - Commercial, 30-day free trial

Cost Comparison:

  • Dynamic IP (Residential): $50-80/month internet service
  • Static IP (Residential): $60-95/month (+$10-15 static fee)
  • Static IP (Business): $150-500/month business fiber

Recommendation:
Use dynamic IP for normal browsing. Upgrade to static only if you:

  • Host servers (web, email, VPN)
  • Run remote access services
  • Operate security cameras accessible externally
  • Need consistent IP for whitelisting

Check your current IP and type with our What is My IP Address tool.

Q4: How do I find out who owns an IP address?

Answer: Use WHOIS lookups to query Regional Internet Registry databases for IP ownership, network details, and abuse contacts.

Method 1: Command-Line WHOIS

# Query IP ownership
whois 8.8.8.8

# Output includes:
# Organization: Google LLC (GOGL)
# Network Range: 8.8.8.0 - 8.8.8.255
# CIDR: 8.8.8.0/24
# Country: US
# Registered: 2014-03-14
# Abuse Contact: network-abuse@google.com

# Query specific RIR
whois -h whois.arin.net 8.8.8.8  # North America
whois -h whois.ripe.net 203.0.113.42  # Europe
whois -h whois.apnic.net 202.12.28.140  # Asia-Pacific

Method 2: Online WHOIS Lookup

Our DNS Lookup Tool provides comprehensive WHOIS data:

  • Organization name and registration details
  • Network CIDR range and allocation date
  • Abuse contact email for reporting malicious activity
  • ASN (Autonomous System Number) for routing analysis
  • Technical and administrative contacts

Method 3: ASN Lookup

# Get ASN from IP
whois -h whois.cymru.com " -v 8.8.8.8"

# Returns: AS15169 | 8.8.8.0/24 | US | arin | 2014-03-14 | GOOGLE

# Query ASN details
whois -h whois.radb.net AS15169

# Shows: All IP ranges owned by Google

What You Can Learn:

1. Network Owner:

  • Company/organization name
  • Registration date and history
  • Network size (CIDR notation)

2. Contact Information:

  • Abuse contact: For reporting spam, hacking, DDoS
  • Technical contact: Network operations team
  • Administrative contact: Business/legal department

3. Network Classification:

  • ASN Type: ISP, hosting, content delivery, enterprise
  • Usage Type: Commercial, residential, government, education
  • IP Allocation: Provider-assigned (PA) vs Provider-independent (PI)

4. Geographic Information:

  • Country of registration (may differ from actual location)
  • RIR region (ARIN, RIPE, APNIC, LACNIC, AFRINIC)

Example Use Cases:

Abuse Reporting:

# Find abuse contact for malicious IP
whois 203.0.113.42 | grep -i "abuse"

# Output: OrgAbuseEmail: abuse@example-isp.com

# Report with details:
# - IP address and timestamp
# - Attack type (DDoS, port scan, spam)
# - Log evidence

Competitive Intelligence:

# Discover competitor's hosting provider
whois 203.0.113.42 | grep -i "organization"

# Organization: Amazon Data Services (AMAZO-4)
# Conclusion: Competitor uses AWS hosting

Security Investigation:

# Identify botnet source
for ip in $(cat suspicious_ips.txt); do
  echo "=== $ip ==="
  whois $ip | grep -i "country\|organization"
done

# Pattern analysis: All IPs from same ASN = compromised hosting account

Privacy Considerations:

WHOIS data for residential ISP blocks shows ISP name only, not individual subscribers:

NetRange: 73.0.0.0 - 73.255.255.255
Organization: Comcast Cable Communications (CCCS)

ISPs don’t disclose which customer uses specific dynamic IP without legal warrant.

For business static IPs, organization details may be public:

NetRange: 203.0.113.0 - 203.0.113.255
Organization: Example Corporation (EXAMP-1)
Address: 123 Business St, San Francisco, CA

WHOIS Privacy Protection:
Small businesses can request privacy via RIR—contact details replaced with proxy registration service.

Related Investigative Tools:

Q5: Can I block specific countries or IP ranges from accessing my website?

Answer: Yes—geoblocking is legal and technically straightforward using web server configuration, firewall rules, or CDN features.

Legal Considerations:

When Geoblocking Is Legal:

  • Copyright licensing: Streaming services enforce regional rights
  • Regulatory compliance: GDPR requires EU visitor consent mechanisms
  • Sanctions compliance: Block countries under economic sanctions (North Korea, Iran, Cuba)
  • Business strategy: Limit service to supported regions

When Geoblocking May Be Illegal:

  • Discrimination: EU law prohibits unjustified geo-discrimination within EU
  • Accessibility: Some jurisdictions require reasonable accommodation
  • Contractual obligations: Check service agreements before implementing

Implementation Methods:

Method 1: Nginx Geoblocking

# /etc/nginx/nginx.conf

http {
    # Load GeoIP2 module
    geoip2 /usr/share/GeoIP/GeoLite2-Country.mmdb {
        $geoip2_country_code country iso_code;
        $geoip2_country_name country names en;
    }

    # Define blocked countries
    map $geoip2_country_code $blocked_country {
        default 0;
        CN 1;  # China
        RU 1;  # Russia
        KP 1;  # North Korea
        IR 1;  # Iran
        # Add more country codes as needed
    }

    server {
        listen 80;
        server_name example.com;

        # Block access from restricted countries
        if ($blocked_country) {
            return 403 "Access denied from $geoip2_country_name";
        }

        location / {
            proxy_pass http://backend;
        }
    }
}

Install GeoIP Module:

# Ubuntu/Debian
sudo apt-get install libnginx-mod-http-geoip2
sudo apt-get install geoipupdate

# Download MaxMind GeoLite2 database
sudo geoipupdate

# Verify database
ls -la /usr/share/GeoIP/

Method 2: Apache Geoblocking

# .htaccess or httpd.conf

<IfModule mod_geoip.c>
  GeoIPEnable On
  GeoIPDBFile /usr/local/share/GeoIP/GeoIP.dat

  # Block specific countries
  SetEnvIf GEOIP_COUNTRY_CODE CN BlockCountry
  SetEnvIf GEOIP_COUNTRY_CODE RU BlockCountry
  SetEnvIf GEOIP_COUNTRY_CODE KP BlockCountry

  <RequireAll>
    Require all granted
    Require not env BlockCountry
  </RequireAll>
</IfModule>

# Alternative: Deny specific IP ranges
<RequireAll>
  Require all granted
  Require not ip 203.0.113.0/24
  Require not ip 198.51.100.0/24
</RequireAll>

Method 3: Cloudflare Geoblocking (No Code)

Cloudflare Firewall Rules:

  1. Log into Cloudflare dashboard
  2. Navigate to Firewall → Firewall Rules
  3. Create new rule: “Block Countries”
  4. Expression: (ip.geoip.country in {"CN" "RU" "KP"})
  5. Action: Block
  6. Deploy rule

Cloudflare Access (Conditional Allow):

# Allow only specific countries
(ip.geoip.country in {"US" "CA" "GB" "AU"})

Cloudflare Rate Limiting by Country:

# Stricter rate limits for high-risk countries
(ip.geoip.country eq "CN") and (http.request.uri.path eq "/login")
Rate: 5 requests per minute

Method 4: iptables Firewall (Linux Server)

# Install ipset for efficient IP list management
sudo apt-get install ipset

# Create country blocklist
sudo ipset create cn hash:net

# Add Chinese IP ranges (example)
sudo ipset add cn 1.0.1.0/24
sudo ipset add cn 1.0.2.0/23
# ... add all CN ranges from RIR data

# Block with iptables
sudo iptables -I INPUT -m set --match-set cn src -j DROP

# Make persistent
sudo apt-get install iptables-persistent
sudo netfilter-persistent save

Automated Country Blocklist Updates:

#!/bin/bash
# /usr/local/bin/update-country-blocklist.sh

# Download country IP ranges from RIPE
curl -s "https://stat.ripe.net/data/country-resource-list/data.json?resource=CN" \
  | jq -r '.data.resources.ipv4[]' > /tmp/cn-ipv4.txt

# Clear existing ipset
ipset flush cn

# Add new ranges
while read range; do
  ipset add cn $range
done < /tmp/cn-ipv4.txt

echo "Updated CN blocklist: $(ipset list cn | wc -l) ranges"

# Run weekly via cron
# 0 3 * * 0 /usr/local/bin/update-country-blocklist.sh

Method 5: Application-Level Blocking (Code)

Python/Flask Example:

from flask import Flask, request, abort
import geoip2.database

app = Flask(__name__)
reader = geoip2.database.Reader('/path/to/GeoLite2-Country.mmdb')

BLOCKED_COUNTRIES = ['CN', 'RU', 'KP', 'IR']

@app.before_request
def geoblock():
    """Block requests from restricted countries"""
    visitor_ip = request.remote_addr

    try:
        response = reader.country(visitor_ip)
        country_code = response.country.iso_code

        if country_code in BLOCKED_COUNTRIES:
            abort(403, description=f"Access denied from {response.country.name}")
    except Exception as e:
        # Allow request if geolocation fails
        pass

@app.route('/')
def index():
    return "Welcome from allowed country"

PHP Example:

<?php
require 'vendor/autoload.php';

use GeoIp2\Database\Reader;

$reader = new Reader('/path/to/GeoLite2-Country.mmdb');
$blocked_countries = ['CN', 'RU', 'KP', 'IR'];

$visitor_ip = $_SERVER['REMOTE_ADDR'];

try {
    $record = $reader->country($visitor_ip);
    $country_code = $record->country->isoCode;

    if (in_array($country_code, $blocked_countries)) {
        http_response_code(403);
        die("Access denied from {$record->country->name}");
    }
} catch (Exception $e) {
    // Allow if geolocation fails
}
?>

Best Practices:

1. Whitelist vs Blacklist Strategy:

  • Blacklist: Block specific high-risk countries (most common)
  • Whitelist: Allow only specific countries (higher security, less flexible)

2. Exemptions:

  • Allow search engine bots regardless of IP (Google, Bing crawlers)
  • Allow payment processors (PayPal, Stripe webhooks)
  • Allow CDN/reverse proxy IPs (Cloudflare, AWS CloudFront)
# Nginx: Allow Googlebot from China
geo $whitelisted_bot {
    default 0;
    # Googlebot IP ranges
    66.249.64.0/19 1;
    64.233.160.0/19 1;
}

if ($blocked_country and !$whitelisted_bot) {
    return 403;
}

3. User Experience:

  • Display clear error messages explaining block reason
  • Provide contact method for legitimate users needing access
  • Consider CAPTCHAs instead of hard blocks for borderline cases

4. Legal Compliance:

  • Document business justification for geoblocking
  • Review EU geo-blocking regulations if operating in Europe
  • Maintain audit logs of block decisions

5. Performance:

  • Use in-memory databases (ipset, MaxMind MMDB) for fast lookups
  • Cache geolocation results for repeated visitors
  • Implement at CDN/WAF level (Cloudflare) for lowest latency

Alternative: Rate Limiting Instead of Blocking:

# Nginx: Stricter limits for high-risk countries
map $geoip2_country_code $rate_limit_zone {
    default general;
    CN high_risk;
    RU high_risk;
}

limit_req_zone $binary_remote_addr zone=general:10m rate=10r/s;
limit_req_zone $binary_remote_addr zone=high_risk:10m rate=2r/s;

server {
    location / {
        limit_req zone=$rate_limit_zone burst=5;
        proxy_pass http://backend;
    }
}

Testing Your Geoblocking:

  • Use VPN to test access from blocked countries
  • Check What is My IP to verify VPN location
  • Monitor server logs for blocked requests: grep "403" /var/log/nginx/access.log
  • Use Selenium Grid with international proxies for automated testing

Related Security Tools:

Conclusion: Mastering IP Address Intelligence

Key Takeaways:

  1. IP geolocation accuracy varies by level—95%+ for country, 55-80% for city, unreliable for postal codes
  2. VPN/proxy detection requires multi-signal approach—database matching (95% accuracy), ASN analysis, WebRTC leaks, latency patterns
  3. Fraud prevention combines IP location with billing address, device fingerprinting, and threat intelligence feeds
  4. Threat intelligence aggregates multiple sources—AbuseIPDB, Spamhaus, AlienVault OTX—for reputation scoring
  5. GDPR compliance requires legitimate interest, data minimization, retention limits (30-90 days), and IP anonymization
  6. Geoblocking is legal for licensing/compliance but requires careful implementation to avoid false positives

Action Plan:

Immediate (Today):

  • Check your public IP with our What is My IP Address tool
  • Test your IP’s geolocation accuracy and VPN detection
  • Review your server logs for suspicious IP patterns
  • Verify GDPR compliance of current IP logging practices

Short-Term (This Week):

  • Implement IP-based fraud detection for e-commerce/auth
  • Configure rate limiting based on ASN and country risk
  • Set up automated IP reputation checking with AbuseIPDB
  • Enable IP anonymization for analytics (mask last octet)
  • Test WebRTC leak detection on your login pages

Long-Term (This Month):

  • Deploy comprehensive threat intelligence integration
  • Implement geoblocking for high-risk countries (if applicable)
  • Configure IP retention policies with automated deletion
  • Set up SIEM integration for IP-based security alerts
  • Document IP processing in privacy policy for GDPR compliance

Related Tools and Guides:

External Authority Resources:

Need Help?

Stay Secure in 2025:

IP address intelligence is evolving—IPv6 adoption, privacy regulations (GDPR/CCPA), and sophisticated VPN/proxy technologies require adaptive security strategies. Start with the basics (accurate geolocation, VPN detection, rate limiting), then progressively enhance with threat intelligence feeds, behavioral analysis, and automated response systems.

Your network security begins with understanding who’s connecting. Check any IP now: IP Address Lookup Tool

About This Guide:

This comprehensive guide covers IP address lookup from fundamentals to advanced security applications. Updated December 2025 with latest GDPR compliance requirements, VPN detection methods, and threat intelligence best practices.

Share This Guide:

  • Twitter - Share IP lookup guide
  • LinkedIn - Professional networking
  • Reddit - r/netsec, r/webdev communities

Internal Link Strategy: This blog post includes 25+ internal links to related Orbit2x tools, distributed naturally throughout content for SEO value and user navigation.

External Authority Links: 30+ references to official sources (RIPE, ARIN, GDPR.eu, MaxMind, Spamhaus) for credibility and E-A-T (Expertise, Authoritativeness, Trustworthiness) signals.

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