A proxy’s job may seem simple—mask your real IP, act as a barrier between you and the web, and keep your identity hidden. But in reality, proxies vary widely in quality. Some are ticking time bombs that are blacklisted, unreliable, or worse, leak your true IP without your knowledge.
For casual browsing, that’s annoying but manageable. But if you’re scraping data, a weak proxy isn’t just inconvenient. It’s a liability that can bring your entire operation to a screeching halt.
Here’s a clear, step-by-step method to check if your proxy is secure and reliable. Follow it to know exactly what you’re working with.

Step 1: Load Your Proxy Into Browser and Check Connection

Professional proxy use demands a professional browser. Create a new profile in Browser like Octo Browser, add your proxy details, then hit “Check Proxy.” This instantly tests your connection and reveals the proxy’s IP location.

Step 2: Hit Google and Other Popular Sites

Next, open Google, run some searches, then jump to eBay, Amazon, Facebook—anything that loads heavy traffic. No loading errors? Great. Your proxy is passing the basics. Any hiccups here? That’s a red flag.

Step 3: Run Your Proxy Through IPQualityScore

Next, visit Google and perform a few searches, then move on to high-traffic sites like eBay, Amazon, and Facebook. If everything loads smoothly without errors, your proxy is working well. If you encounter any issues or delays, it could indicate a problem.

Step 4: Cross-Check Against Spam Blacklists

Spam databases are the silent killers. If your IP is on one, email blocks and security flags will follow. Check these trusted lists:
Spamhaus
Spamcop
DNS Checker
PixelScan (IP Check section)
For power users, iplists.firehol.org offers a massive database, but you’ll need some scripting skills to use it fully.

Step 5: Identify the ASN Type

The proxy’s origin matters. Use IPinfo or db-ip to look up the ASN type. Residential ISP IPs blend in naturally and trigger fewer alarms. Data center IPs scream “proxy” to many platforms, increasing your risk of getting flagged.

Step 6: Check for DNS Leaks

Even the best proxy fails if DNS requests bypass it, revealing your real IP. Use an open-source tool like DNS Leak Test to confirm all DNS queries route through your proxy.

Step 7: Inspect MTU Values to Spot Fingerprinting Risks

MTU—Maximum Transmission Unit—determines packet size without fragmentation. Standard values like 1500 for Ethernet or 1480 for PPTP are common for direct connections. Some proxies tweak MTU to avoid fragmentation, which can signal proxy use.
Browserleaks and similar tools display MTU under TCP/IP Fingerprint. Aim for standard values to avoid suspicion.

Conclusion

Proxy quality goes beyond hiding your IP. It’s about maintaining trust with security systems, staying stealthy, and avoiding detection. Poor proxies can lead to banned accounts and wasted effort. Because each platform has its own rules, always test your proxy on the specific sites you plan to use. Minor flaws might seem harmless—until they cause problems. Staying vigilant is crucial to keeping ahead.