Detecting Residential Proxies: Unmasking Fraudulent IP Addresses

Detect fraudulent IP addresses such as residential proxies, VPN connections, and similar abusive anonymous connections.

Introduction to Fraudulent IP Addresses

The internet has become a hotbed for fraudulent activities, with fraudsters constantly finding new ways to conceal their true identities. One such method is through the use of residential proxies, which mimic genuine residential DSL or cable connections (like Comcast, Spectrum, etc.) as opposed to typical fraudulent IP addresses which are hosted on servers in data centers. These proxies pose a significant threat to businesses and individuals alike, as they can be used to bypass security measures, engage in illegal activities, and manipulate online systems.

Residential Proxy Detection

In this article, we will explore the concept of residential proxies, understand why they are a cause for concern, and delve into the various methods available to detect and identify these fraudulent IP addresses. By gaining a deeper understanding of proxy detection techniques, businesses can better protect against fraud to safeguard their operations.

The Rise of Residential Proxy Networks

Residential proxy networks have gained prominence in recent years, primarily driven by their support for the scalping market. Scalping involves purchasing limited stock items, such as shoes, GPUs, and gaming consoles, in bulk and reselling them at significantly higher prices. To carry out these activities, scalpers rely on residential proxies that can bypass anti-scalper checks on popular websites.

The motivation behind the proliferation of residential proxy services is clear - financial gain. These services charge users a monthly fee for access to a single residential proxy IP address. With numerous providers in the market, offering proxies capable of circumventing anti-scalper checks, the operators of these networks reap substantial profits by reselling products at inflated prices. Unfortunately, this practice directly harms genuine consumers, who are left paying exorbitant prices or struggling to secure the products they desire.

The Importance of Detecting Residential Proxies

Detecting residential proxies is crucial for businesses across various industries. By understanding how users connect to their websites and applications, organizations can identify potential threats and take proactive measures to mitigate risks. Proxy detection enables businesses to answer vital questions, including:

  • Is the user genuinely located where they claim to be?
  • Are they attempting to access restricted services?
  • Are they using suspicious technologies to change their IP addresses?
  • Are they likely to be fraudsters or cybercriminals?

By combining proxy detection with other methods, such as risk scoring, identity verification, and behavior analysis, businesses can gain a comprehensive view of potential threats and enhance their fraud prevention efforts. This multi-faceted approach helps reduce risks, improve compliance, and minimize the cost of fraud. IPQS provides a quick glimpse into our IP risk scoring through our online lookup tools.

Detect Residential Proxies

Methods for Detecting Residential Proxies

1. Inspecting Source Networks (ASN)

Websites targeted by fraudulent activities, including scalping, have implemented comprehensive measures to detect and block malicious IP addresses. One common and effective method is inspecting the source network, known as the Autonomous System Number (ASN), from which the IP address originates. By cross-referencing the ASN with known proxy networks, businesses can filter out suspicious connections.

However, fraudsters are always one step ahead. They collaborate with hosting providers willing to announce their proxy IP addresses directly on common residential networks, making them appear legitimate. Additionally, they may contract directly with residential networks and colocate server infrastructure in data centers. This clever tactic allows them to bypass traditional detection methods based solely on ASN inspection using an IP address lookup.

2. Monitoring False Negatives and False Positives

To accurately detect residential proxies, businesses must monitor false negatives and false positives. False negatives refer to genuine residential proxy IP addresses that are incorrectly classified as genuine residential IPs. Monitoring the rate of false negatives provides insights into the effectiveness of the proxy detection system.

On the other hand, monitoring false positives is more challenging. When an IP address is flagged as a residential proxy but not identified as such by other ML models or heuristics, it can either indicate a newly discovered proxy or a classification error. Measuring the direct false positive rate is difficult since the true nature of the IP address is unknown. However, a correlated metric can be measured to assess the relative performance of the detection system.

3. Statistical Analysis and Performance Comparison

To evaluate the performance of a proxy detection system, statistical analysis can be employed. By comparing the CAPTCHA passed rates of the ML model with those of the ground truth labels (IPs known to be proxies), businesses can determine whether the ML model's performance is significantly different from that of the proxy provider.

This analysis involves creating blocking patterns for each proxy provider and the ML model, using common signatures to identify suspicious traffic. The CAPTCHA passed rate is then monitored, and statistical tests, such as the Student's t-test, are performed to measure the difference in mean between the ML model and the proxy provider to identify malicious IP addresses.

When the performance of the ML model begins to decline, indicating a higher false positive rate, an automatic alert is triggered to initiate model retraining based on recent data. This retraining process helps improve the ML model's accuracy and adaptability to evolving proxy detection challenges.

Use Cases and Impact

The detection of residential proxies has far-reaching implications for various industries. Let's explore some use cases and understand the impact of effectively detecting and combating fraudulent proxy usage.

1. E-commerce and Scalping Prevention

One of the most prominent use cases is in the e-commerce industry, where the prevalence of scalping poses a significant challenge. By accurately detecting residential proxies used by scalpers, online retailers can implement measures to limit their impact. This includes restricting purchases to a reasonable quantity per customer, implementing CAPTCHA systems, and monitoring suspicious activities. Bot IP addresses can also provide insight into past abusive behavior for scraping, chargebacks, account takeover (ATO), and similar abuse.

Detecting and blocking residential proxies helps level the playing field for genuine consumers, allowing them fair access to limited stock items at reasonable prices. By reducing the influence of scalpers, online retailers can enhance customer satisfaction and maintain a positive brand image.

2. Cybersecurity and Fraud Prevention

Residential proxies are not limited to scalping activities; they are also utilized by cybercriminals and fraudsters to carry out illegal activities. By effectively detecting these proxies, organizations can strengthen their cybersecurity defenses and prevent various forms of fraud, including account takeovers, credit card fraud, and identity theft.

Proxy detection serves as an essential component of a comprehensive fraud prevention strategy. By combining proxy detection with other security measures, such as user behavior analysis, VPN identification, anomaly detection, and identity verification, businesses can create robust barriers against fraudulent activities.

3. Geo-blocking Circumvention

Residential proxies are often used to bypass geo-blocking restrictions imposed by online platforms. By detecting and blocking these proxies, businesses can enforce their geo-blocking policies and ensure compliance with legal and licensing requirements. This helps protect intellectual property rights, prevent unauthorized access to content, and maintain regional pricing strategies.


Detecting residential proxies is crucial for businesses looking to protect themselves from fraud, safeguard their operations, and ensure fair access to their products and services. By implementing robust proxy detection systems and combining them with other fraud prevention measures, organizations can effectively combat fraudulent activities, such as scalping, cybercrime, and geo-blocking circumvention.

As technology evolves and fraudsters become more sophisticated, continuous research and development in proxy detection methods are essential. By staying ahead of the curve and continuously refining their detection systems, businesses can minimize the impact of fraudulent proxy usage and maintain a secure online environment for their customers.

Remember, the battle against fraudulent proxy usage is an ongoing one, requiring vigilance, adaptability, and a multi-layered approach to fraud prevention. By investing in advanced proxy detection technologies and leveraging the power of data analysis, businesses can stay one step ahead of fraudsters and protect their interests in an ever-evolving digital landscape.


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