No single app is permanently "the one that works" — ISPs filter by protocol fingerprint, so whichever free app is popular this week gets detected and blocked soon after. What stays working is the
protocol, not the brand: VLESS + Reality on port 443 has survived multiple filtering waves because it is indistinguishable from normal HTTPS. If your VPN suddenly drops, the fix is switching to a DPI-resistant protocol with a fallback, not hunting for the next free app. Full answer:
best VPN for Iran 2026.