Blocking illegal gambling sites sounds like a policy decision, but in practice, it’s an engineering challenge. From DNS interference to payment blocks and deep packet inspection, countries are deploying increasingly complex technical tools to disrupt access to offshore gambling platforms. Some are building layered defence systems, while others are still catching up.

But even as enforcement gets smarter, the question lingers - is it working? Operators adapt. Domains shift. VPNs blur borders. And decentralised platforms are already rewriting the rules entirely.

This article explains the actual technologies governments use to block illegal gambling sites, one layer at a time. It also asks the harder questions: What’s working? What’s falling short? And as AI, blockchain, and adtech enter the enforcement picture, are we creating stronger safeguards, or simply shifting it somewhere harder to detect? Let’s break it down.

Why Blocking Offshore Gambling Matters

​The battle against offshore gambling remains a pressing concern for regulators worldwide in 2025. Despite significant strides in legalising and regulating online gambling in various jurisdictions, unlicensed operators continue to thrive, exploiting regulatory gaps and technological loopholes.​

These unregulated platforms pose substantial risks. The European Commission has identified online gambling as a high-risk sector for money laundering and terrorist financing, particularly highlighting the rise in unlicensed sites that bypass customer due diligence and reporting requirements. Such operations not only facilitate illicit financial activities but also result in significant losses of tax revenue for governments.

For licensed operators, the existence of these illegal sites undermines efforts to promote responsible gambling and maintain industry integrity. Players drawn to unregulated platforms often face issues like unfair game practices, a lack of dispute resolution mechanisms, and potential data breaches.

For these reasons and more, there is mounting political and public pressure on authorities to act decisively. In the United States, regulators from seven states have urged the Department of Justice to prioritise actions against illegal offshore gambling, emphasising the need to protect consumers and uphold the rule of law.

In short, while the regulated iGaming sector continues to evolve, the persistent threat of offshore gambling necessitates advanced technical measures and international collaboration to safeguard both the industry and its stakeholders.

Core Methods Used to Block Illegal Gambling Sites

Blocking access to offshore gambling sites is rarely a one-size-fits-all effort. Countries typically adopt a layered, technical approach, each tailored to local infrastructure, political need, enforcement capabilities, and perceived threats to jurisdictional control. Here are the most common methods used to block illegal (offshore) platforms:

DNS Blocking: The First Line of Defence

DNS blocking works by intercepting requests to specific domain names and preventing them from resolving to their actual IP addresses. When someone tries to access a blocked gambling site, the DNS server may return an error or redirect them to a warning page, typically hosted by their internet service provider (ISP). This method is widely used in many locations worldwide, especially in Europe, Asia, and Latin America. 

While DNS blocking can deter casual users, it’s far from foolproof. Switching to public DNS services, such as Google or Cloudflare, can instantly bypass restrictions. Furthermore, determined tech-savvy users may even turn to VPNs or encrypted DNS queries to bypass filters entirely. As a result, DNS blocking functions best as a first line of defence, and one that needs to be reinforced with more sophisticated tools to hold the line.

IP Blocking and Geo-Fencing

IP blocking and geo-fencing are standard tools that restrict access to unlicensed gambling sites based on a user's geographic location. By identifying and filtering IP addresses associated with specific regions, authorities can prevent users within their jurisdiction from accessing prohibited content.​ This approach is used in countries like Italy, Norway, and Singapore, where regulators have mandated that ISPs block access to certain gambling websites. For instance, Norway's Lotteritilsynet has ordered the blocking of 57 illegal gambling websites operating unlawfully within the country. 

However, like geo-fencing, the effectiveness of IP blocking is limited by how easily users can circumvent these measures. Many individuals use Virtual Private Networks (VPNs) or proxy servers to mask their true location, rendering IP-based restrictions less effective. In addition, the dynamic nature of IP addresses and the use of Content Delivery Networks (CDNs) by websites can complicate enforcement efforts.​

Deep Packet Inspection and Layer-7 Filtering

Deep Packet Inspection (DPI) and Layer-7 filtering go beyond surface-level data by scrutinising the actual content of internet traffic to identify and block specific activities, such as access to unlicensed gambling sites. Unlike traditional methods that examine only headers, DPI analyses the full data packet, giving authorities the means to detect and obstruct prohibited content with high accuracy.​

This technique is commonly used in countries with strict internet controls, such as China and Iran. China's ‘Great Firewall’, for instance, uses DPI to monitor and filter traffic, effectively blocking access to unauthorised gambling platforms and other restricted content. Similarly, Iran implements DPI at international gateways to enforce its internet censorship policies.​

While DPI offers precise control, it nonetheless raises significant concerns regarding privacy and civil liberties. The method's invasive nature can lead to overblocking, which affects legitimate services and stifles free expression. Moreover, implementing DPI requires substantial infrastructure and technical expertise, posing significant challenges for widespread adoption.​

Payment Blocking and Merchant Code Filtering

Payment blocking and merchant code filtering are widely used to cut off the financial infrastructure supporting unlicensed gambling operators. By instructing payment service providers (PSPs), card schemes, and banks to reject transactions linked to specific merchant category codes (MCCs), regulators can interrupt deposits and withdrawals at the source. This method is standard in countries like Brazil, India, and several European Union member states.

In Brazil, for example, the Central Bank collaborates with Pix and major financial institutions to freeze payments tied to offshore betting activity. Similarly, across the EU, authorities in France and the Netherlands, among others, have adopted similar approaches, using financial surveillance to flag and restrict high-risk transfers.

That said, the flexibility of illegal operators is a significant limitation. Crypto wallets, third-party processors, and anonymised payment methods remain hard to police. As evasion methods evolve, success depends less on brute enforcement and more on real-time monitoring, regulatory coordination, and cooperation across the payment systems.

App Store Removals and Mobile Access Limits

As mobile gambling surges, regulators are targeting app stores and mobile networks to curb unlicensed betting. In the Netherlands, the Kansspelautoriteit (KSA) has removed 20 illegal gambling apps from app stores since the start of 2025. These apps are often presented as harmless games or misused logos of licensed operators like Holland Casino to deceive users. Once installed, they redirected players to unregulated gambling sites, posing risks, especially to minors.

Beyond app removals, some jurisdictions are exploring mobile network-level interventions. By collaborating with Internet Service Providers, regulators aim to block access to illegal gambling sites over 4G and 5G networks, adding another layer of defence.​

However, these measures also face limitations. Users can bypass restrictions using VPNs or by sideloading apps (manually installing mobile applications) outside official stores. Moreover, the dynamic nature of app development means that new illicit apps can quickly replace those that have been removed. Thus, while app store removals and mobile access limits are practical methods, they must be part of a broader enforcement strategy.

Domain Seizure and Sinkholing

Domain seizure and sinkholing represent more assertive tactics in the fight against illegal online gambling. Rather than merely blocking access, authorities legally take control of offending domain names, redirecting users to official warning pages or controlled servers known as sinkholes.​

This approach is often used in collaboration with domain registrars such as Verisign or through court orders. A notable example is the US Department of Justice's 2011 action against major online poker sites, including PokerStars and Full Tilt Poker, where .com domains were seized and replaced with federal seizure notices. 

While effective, this method has its limitations. Its success largely depends on the domain's jurisdiction. Domains registered outside cooperative regions may be able to evade such actions. Furthermore, operators can still quickly migrate to new domains, making sustained enforcement challenging.

Browser-Level Blocking and Warning Systems

As users increasingly turn to mobile browsers to access gambling platforms, sometimes to circumvent app store restrictions, regulators are collaborating more closely with tech companies to implement browser-level blocking and warning systems. Services like Google Safe Browsing and Microsoft Defender SmartScreen play central roles in this strategy.​

Google Safe Browsing, for instance, maintains a dynamic list of URLs associated with malware and phishing. When users attempt to visit a flagged site, browsers like Chrome display a warning that cautions them about potential risks. Similarly, Microsoft Defender SmartScreen checks websites against a constantly updated list of reported phishing and malicious software sites, blocking access when a match is found.

These systems rely on data from user reports, government submissions, and automated detection to identify and flag illicit gambling domains. While not foolproof since users can sometimes bypass warnings, they add a significant hurdle for unlicensed operators. By introducing friction at the browser level, these measures complement other enforcement tactics, making it more challenging for illegal gambling sites to reach potential players.

Countries Leading the Digital Crackdown

Some countries talk tough about illegal gambling, but these three countries are actually taking action. From Italy’s payment bans to Singapore’s deep-packet filtering, here’s how the most assertive jurisdictions are using tech to shut the back door on illegal platforms.

Italy 

Consistent IP and Payment Enforcement

Italy is one European country that has long taken a structured, no-nonsense stance on illegal online gambling, largely driven by the communications authority AGCOM. Through a combination of IP and DNS blocking, advertising restrictions, and payment bans, Italy has built one of Europe’s more aggressive enforcement models.

ISPs are legally required to block access to blacklisted domains, and AGCOM regularly updates this list to keep pace with mirror sites and new URLs. Payments are another pressure point. Italian authorities work closely with banks and card networks to stop financial transactions between players and unlicensed platforms.

The country’s advertising clampdown has also drawn attention. In 2023, AGCOM fined Google €2.25 million for violating ad restrictions, and Twitch was penalised for similar breaches. Italy’s model isn’t perfect, but its consistency and cross-channel coordination make it a leader in digital enforcement.

Brazil

The Big Push After Legalisation

Following the legalisation of fixed-odds betting, Brazil has intensified its efforts to curb unlicensed operators. The National Telecommunications Agency (Anatel), in collaboration with the Secretariat of Prizes and Bets (SPA), has blocked over 5,200 illegal gambling sites since October 2024 and submitted over 12,500 domain names for blocking. This initiative is part of a broader strategy to ensure that only authorised entities operate within the country's regulated market.​

Beyond domain blocking, Brazil has implemented stringent payment restrictions. Operators are prohibited from accepting deposits via credit cards or cryptocurrencies, forcing them to use approved methods, such as Pix, the national instant payment system. This measure aims to prevent financial transactions with unlicensed platforms and enhance consumer protection.​

To further strengthen enforcement, Anatel and SPA signed a Technical Cooperation Agreement in December 2024. This pact facilitates a rapid exchange of information, enabling swift action against illegal operators. Despite these moves, enforcement has struggled to keep pace. Domain cycling, evasive hosting, and fragmented oversight across Anatel, COAF, and the judiciary have made coordinated crackdowns difficult.

Singapore

A Controlled Model Built on DPI

Singapore doesn’t just block illegal gambling sites. It tracks, filters, and neutralises them with quiet precision. In early 2025, under the Gambling Control Act 2022, enforcement powers shifted to the Singapore Police Force, giving authorities more direct control to dynamically block offshore operators in real time.

But it’s not just about pulling the plug. Singapore’s tech stack goes deeper, deploying tools like DPI and Layer-7 filtering to inspect traffic, flag gambling-related activity, and take down access with remarkable speed and efficiency. On mobile devices, ISPs are enlisted to enforce network-level filtering, while VPN detection tools catch attempts to sneak around the system.

Over 3,800 gambling sites and SGD 37 million worth of transactions have already been blocked using these methods. Despite these efforts, the tech battle never really ends, even in strict jurisdictions like Singapore, new domains continue to appear just as quickly as old ones disappear.

The Limits of Technical Enforcement

For all the blocking, filtering, and blacklisting, even the most sophisticated enforcement tools struggle to keep pace with the agility of illegal gambling operators since they generally know exactly where to hide. Mirror domains are the most obvious loophole. Block one site, and within hours, its clone pops up under a new URL. Brazil’s crackdown is a prime example. Despite efforts to block over 12,500 domains, around 80% remain accessible through redirects, Telegram links, or slightly modified names.

Then there’s also the VPN problem. When Brazil temporarily blocked X (formerly Twitter) in 2024, VPN usage shot up 1,600% in a single day, highlighting just how quickly users adapt when access is restricted. Over-blocking, on the other hand, adds a different kind of problem. In Greece, efforts to filter gambling content inadvertently shut off access to non-gambling sites, causing public backlash and revealing just how imprecise these systems can be.

Meanwhile, decentralised hosting and crypto wallets have moved the goalposts again. Some platforms now run on blockchain-based systems with no central server to target. Payments flow anonymously through crypto, making traditional financial surveillance look inadequate. These challenges emphasise the limitations of relying solely on technical measures. To make real progress, countries will need to pair smart tools with stronger laws and work together to close the gaps that offshore operators keep slipping through.

Where the Real Risk Lies for Legitimate Brands

Blocking offshore sites may seem like someone else’s problem, but licensed operators know it doesn’t always play out that way. Brand confusion is real. Illegal operators frequently hijack well-known names, mirror landing pages, or deploy misleading affiliate strategies across Telegram, social media, or paid ads. For the average user, the line between what is legitimate and what is illegal isn’t always clear. That confusion doesn’t just harm player trust, it also reflects poorly on the brand being imitated.

This is where blocklist monitoring earns its place within operational procedures. Regulators like Switzerland’s ESBK and Comlot maintain active ISP-level blocks and publish updated blocklists. These lists don’t just target unlicensed operators, they offer early warning signs. Affiliates linking to blocked domains, even indirectly, can put you in the regulatory crosshairs.

Meanwhile, the wider compliance net is tightening. Payment service providers are under pressure to clamp down on irregular payment activity. Digitised advertising networks are increasingly risk-averse, applying automated filters that can restrict campaigns based on domain reputations, past violations, or country-level directives. If your site shares any proximity, either technical, geographic, or visual, to blocked entities, you may be caught in a filter you never saw coming.

That’s why resilience needs to be more than a backup plan. Build domain redundancy into your infrastructure. Establish clear affiliate guidelines with actual oversight. Make your payment pathways traceable and defensible.

Put legal clarity front and centre across your stack, from frontend UX to backend processing. In a regulatory climate that’s moving faster than enforcement can keep up, being technically compliant isn’t always enough. You need to be verifiably above board at every level.

Could Tech Advances Rewire the Rules?

There’s no shortage of enforcement tools on the market in 2025, but some of the most interesting ones aren’t reactive. They’re predictive. AI, for example, is no longer just crunching numbers in the background. It’s being trained to detect the behavioural signatures of illegal gambling, flagging irregularities in affiliate traffic, unusual domain clusters, or even promo language that mimics licensed brands. In the hands of regulators, that’s a decisive edge. For operators, it could soon become a line of defence.

Then there’s blockchain, and with it, a different kind of problem. Domains like .crypto don’t live on ICANN infrastructure. You can’t blacklist them through traditional DNS controls. They don’t answer to registrars. For enforcement, that changes the game since this type of loophole doesn’t go unnoticed.

The fundamental question remains: Are we inching toward a globally coordinated enforcement layer? Maybe. Cross-border data-sharing is already happening quietly in the background, particularly in payment compliance circles. But decentralised systems evolve far faster than regulators can ever respond, let alone coordinate. And as enforcement efforts ramp up, there’s a growing risk that authorities start viewing every new technology as a potential threat, rather than a tool to understand. That kind of pressure doesn’t just impact bad actors, it also makes licensed operators more cautious. Some may scale back innovation. Others may shift to structures that are harder to monitor.

The rules are changing, no doubt. But the real question is whether we’re creating better ones or just moving the goalposts and whether regulation can keep pace with the technology it’s trying to contain.

The Clean Tech Stack That Regulators Want to See

Altenar’s modular sportsbook technology helps licensed operators stay ahead in an environment where enforcement alone isn’t enough. From domain redundancy and payment traceability to affiliate oversight and compliance-ready integrations, our platform is built to support transparent, adaptable, and legally sound operations, giving you the tools to compete without getting caught in the crossfire.

Book a private demonstration today and see how Altenar’s compliance-ready sportsbook can help you outmanoeuvre risk, streamline operations, and stay ahead of offshore threats.