Setting up a traffic filtering system can feel overwhelming with dozens of filter options available. But not all filters carry equal weight. Here are the five most impactful filters that should be the foundation of every campaign's protection strategy.
1. GeoIP Filtering
Geographic filtering is the first line of defense. If your offer targets US traffic, there's no reason to let visitors from other countries through to your offer page. Premium GeoIP databases provide country, region, and city-level precision.
Beyond simple country blocking, advanced GeoIP filtering lets you target specific regions or cities. This is particularly useful for local offers or when you know your audience is concentrated in specific areas. Set up your allowed countries first — it's the simplest filter with the highest impact.
2. VPN and Proxy Detection
VPN and proxy traffic is one of the biggest threats to campaign accuracy. Ad reviewers, competitors, and sophisticated bots frequently use VPNs to mask their real location. A good proxy detection database can identify VPN services, public proxies, Tor exit nodes, and datacenter IP ranges.
The key metric here is database freshness. VPN providers regularly rotate their IP addresses, so your detection database needs frequent updates. Look for a service that updates its threat intelligence database daily or more frequently.
3. Bot Detection
Bot detection goes beyond simple user-agent checks. Modern bots can mimic real browsers with legitimate-looking user agents. Effective bot detection combines multiple signals: known crawler signatures, behavior patterns, JavaScript execution checks, and comparison against databases of known bot networks.
A good bot filter catches not just obvious crawlers like Googlebot, but also headless browsers, automated testing tools, and commercial scraping services that try to look like real users.
4. Device and OS Filtering
Device fingerprinting adds another layer of validation. If your offer is a mobile app, you probably don't want desktop traffic. If you're targeting iOS users, Android traffic is wasted spend.
Device filtering examines the user agent, screen resolution, and other device signals to classify visitors. Combined with OS filtering, you can ensure only relevant device types reach your offer page. This is especially important for app install campaigns where the wrong platform means zero conversions.
5. Rate Limiting
Rate limiting prevents the same visitor from hitting your page repeatedly. Legitimate users typically visit once or twice. If the same IP address is making dozens of requests, it's almost certainly automated traffic.
Configure sensible limits — for example, 3 visits per IP per hour. This catches simple bot attacks without affecting real users. Combined with the other four filters, rate limiting provides a solid baseline protection for any campaign.
Putting It All Together
These five filters work best as a pipeline, evaluated in order: GeoIP first (cheapest check), then VPN/proxy detection, bot analysis, device validation, and finally rate limiting. This priority ordering ensures the fastest possible verdict — if a visitor fails the GeoIP check, there's no need to run expensive bot analysis.
Start with these five filters, monitor your analytics, and add more specific filters (ISP, referer, language, timezone) as you learn more about your traffic patterns.