What is an IP Blocklist?
An IP blocklist (also called IP blacklist or deny list) is a curated database of IP addresses identified as sources of malicious traffic, bots, proxies, VPNs, data center IPs, or known fraud actors. Fraudlogix IP Blocklist enables pre-bid blocking—filtering bad traffic before it generates impressions, clicks, or consumes resources. Organizations use blocklists to prevent bot traffic, ad fraud, account takeover attempts, and other malicious activities at the network level.
How IP Blocklists Work
IP blocklists operate at the network level, intercepting traffic before it reaches applications or generates billable events. When a connection attempt arrives, the system checks the source IP address against the blocklist database. If the IP appears on the list, the connection is immediately rejected. This happens in milliseconds—fast enough to prevent impression generation in programmatic advertising or block fraudulent login attempts before authentication processes begin.
Fraudlogix IP Blocklist contains millions of confirmed malicious IP addresses, continuously updated from global threat intelligence. The database includes botnet infrastructure, data center ranges used for fraud, proxy and VPN services, click farms, and IPs observed attacking honeypots. This comprehensive coverage blocks the vast majority of bot traffic and automated fraud before it impacts your systems.
Pre-Bid vs. Post-Bid Blocking
Pre-bid blocking filters traffic before ad auctions occur. When a publisher's ad server receives a bid request, it first checks the IP against a blocklist. Malicious IPs are rejected before advertisers see the impression, preventing fraudulent auctions entirely. This protects advertiser budgets and publisher reputation simultaneously.
Post-bid blocking happens after impressions are served and fraud is detected. While advertisers may receive refunds, the fraud has already consumed resources, wasted auction capacity, and potentially damaged campaigns. Pre-bid blocklists are dramatically more efficient—they stop bad traffic at the gate rather than cleaning up after fraud has occurred.
The industry is moving away from "blacklist" terminology toward "blocklist" or "deny list." These terms describe the same concept—lists of prohibited IP addresses—but avoid problematic connotations. Modern security professionals prefer blocklist as the standard term.
What Gets Blocked
Data Center IPs
Data center IP addresses from hosting providers, cloud services (AWS, Google Cloud, Azure), and dedicated server facilities. Legitimate users don't browse from data centers—traffic from these IPs typically indicates bots, scrapers, or fraud operations. Fraudlogix IP Blocklist includes comprehensive data center ranges to block this non-human traffic.
Known Bot Networks
IP addresses associated with documented bot networks and click fraud operations. Once security researchers identify bot infrastructure, those IPs are added to blocklists. This includes command and control servers, bot hosting providers, and IP ranges used by fraud-as-a-service operations.
Proxy and VPN Services
Commercial proxy and VPN services that anonymize user location. While VPNs have legitimate privacy uses, they're also heavily used by fraudsters to mask their true location and evade detection. Organizations can choose whether to block all VPN traffic or only suspicious VPN usage based on their risk tolerance.
Click Farms
IP addresses from click farms—facilities where workers or bots generate fraudulent clicks and impressions. These operations concentrate in specific geographic regions and IP ranges, making them identifiable and blockable through comprehensive blocklists.
Compromised Residential IPs
Residential IP addresses confirmed as compromised and participating in botnets. These are more challenging to identify than data center IPs but represent significant threats. Quality blocklists like Fraudlogix's include verified residential IPs observed engaging in malicious activity while excluding legitimate residential traffic.
🛡️ Block Bots & Fraud with Fraudlogix IP Blocklist
Fraudlogix IP Blocklist provides pre-bid protection against bot traffic, data center IPs, proxies, VPNs, and known fraud sources. Continuously updated from global threat intelligence, our blocklist integrates seamlessly with programmatic platforms, ad servers, and web applications—blocking millions of malicious IPs before they impact your business.
Benefits of IP Blocklists
Pre-Bid Protection
Block fraudulent traffic before it generates impressions or clicks. Pre-bid filtering prevents wasted ad spend, reduces server load, and eliminates fraud at the source. Advertisers avoid paying for bot traffic, publishers maintain clean inventory, and platforms reduce processing overhead.
Instant Implementation
IP blocklists deploy quickly without complex integration. Most ad servers, platforms, and applications support blocklist integration through simple IP range uploads or API connections. Protection begins immediately once the blocklist is active.
Continuously Updated
Threat actors constantly acquire new infrastructure. Effective blocklists update frequently—hourly or even more often—to maintain protection against emerging threats. Fraudlogix IP Blocklist updates continuously, ensuring your defenses stay current as the threat landscape evolves.
Cost-Effective Defense
IP blocklists provide excellent ROI. The cost of blocklist subscriptions is minimal compared to losses from bot traffic and fraud. By blocking bad traffic before it consumes resources, blocklists reduce infrastructure costs, prevent wasted ad spend, and protect revenue across all channels.
IP Blocklist Use Cases
Programmatic Advertising
Publishers use pre-bid blocklists to filter bot traffic before ad auctions. This protects advertiser relationships, maintains inventory quality, and ensures header bidding partners see only legitimate impressions. Clean inventory commands higher CPMs and attracts premium demand.
Website Protection
Block malicious bots from accessing websites entirely. Scrapers, content thieves, vulnerability scanners, and DDoS sources are rejected at the edge, preventing them from consuming bandwidth, stealing content, or probing for vulnerabilities. This reduces server load and protects intellectual property.
Account Security
Block credential stuffing attacks, brute force login attempts, and account takeover campaigns by rejecting traffic from known attack infrastructure. Blocklists provide an additional layer of security beyond password policies and multi-factor authentication.
E-commerce Fraud Prevention
Prevent e-commerce fraud by blocking traffic from data centers, proxies, and known fraud sources. Card testing attacks, inventory scrapers, and scalper bots all operate from identifiable IP ranges that blocklists can prevent from reaching checkout systems.
Advertising Fraud & Affiliate Fraud
Entities handling massive transaction volumes—SSPs, DSPs, ad exchanges processing billions of impressions, affiliate tracking platforms managing millions of clicks, and affiliate networks monitoring countless events—need scalable fraud prevention. Fraudlogix IP Blocklist makes it possible to affordably monitor billions of transactions at a predictable, flat fee. Rather than paying per-transaction for behavioral analysis, blocklists provide cost-effective pre-filtering that scales effortlessly from millions to billions of events without proportional cost increases.
Form Spam Protection
Block automated form submissions from bots. Contact forms, registration pages, and survey systems face constant bot spam. IP blocklists prevent the majority of automated submissions without requiring CAPTCHA challenges that degrade legitimate user experience.
Blocklist Best Practices
Use Continuously Updated Lists
Stale blocklists quickly lose effectiveness. Use providers that update hourly or more frequently. Fraudlogix IP Blocklist updates continuously from global threat intelligence, ensuring protection against emerging threats as they appear.
Monitor False Positives
Track legitimate traffic blocked by your blocklist. If false positive rates exceed 0.1-0.5%, investigate blocklist quality or adjust blocking policies. Balance security with accessibility based on your use case and risk tolerance.
Add Your Own Observation Data
Supplement Fraudlogix IP Blocklist with IPs observed attacking your own systems. While Fraudlogix provides comprehensive global threat intelligence, adding your own observation data captures threats specific to your environment and attack patterns targeting your particular infrastructure.
Implement Pre-Bid When Possible
For programmatic advertising, implement pre-bid filtering rather than post-bid detection. Pre-bid blocklists prevent fraudulent auctions entirely, protecting advertiser budgets and platform resources. Post-bid detection still incurs costs that pre-bid blocking avoids.
Review and Audit Regularly
Periodically review blocklist effectiveness. Track metrics like fraud reduction, false positive rate, and blocked traffic volume. Audit blocklist sources and update providers if quality declines. Effective blocklists require ongoing management, not set-and-forget deployment.
Frequently Asked Questions
Building effective blocklists requires significant resources. You need global threat intelligence, honeypot networks, abuse report analysis, and continuous updating infrastructure. Most organizations get better protection at lower cost using commercial blocklists like Fraudlogix's that aggregate intelligence from multiple sources. However, you should supplement commercial lists with IPs observed attacking your own systems.
It depends on your use case. Blocking all VPNs maximizes security but blocks some legitimate privacy-conscious users. Consumer services typically allow VPNs. High-security applications, financial services, or advertising platforms often block VPNs due to high fraud rates. You can also take a middle approach—allowing VPNs but requiring additional verification (MFA, CAPTCHA) for VPN traffic.
Implement a whitelist for known legitimate IPs—your own corporate network, important partners, or verified customers. Monitor support tickets related to access issues. Work with your blocklist provider to report false positives for removal. For high-value users experiencing blocks, consider alternative verification methods (email confirmation, phone verification) rather than removing IPs from blocklists entirely.