We Put Colitu's VPN Verification to the Test. Here's What Changed.
We Put Colitu's VPN Verification to the Test. Here's What Changed. Good engineering gets stronger when people challenge it. On October 10, 2026, a DEV Community member, @launchgatecheck , suggested an interesting test for Colitu's VPN connection verification system. The question was simple but important: What happens if a VPN handshake succeeds, but the tunnel itself cannot carry traffic? Could…
We conducted an experiment to evaluate Colitu's VPN connection verification system. @launchgatecheck, a DEV Community member, proposed an intriguing test scenario: what happens when a VPN handshake is successful, but the tunnel cannot transmit data? To investigate, we created a controlled setting where a VPN server accepted the handshake but internally stopped traffic. We also tested automatic server switching, DNS routing, and network adjustments. The examination revealed three key areas needing enhancements.
1. Tunnel-bound verification: We observed a problem where certain verification requests could be influenced by split-tunneling guidelines, leading to incorrect connection reports. We rectified this by implementing a specialized, tunnel-bound verification path that is impervious to conventional routing adjustments.
2. Network transition recovery: We enhanced the Windows application's response to Wi-Fi adapter connections on various networks. Colitu now quickly identifies address and gateway changes, invalidates prior verification, and initiates reconnection.
3. DNS consistency: Our tests indicated an opportunity to refine DNS handling on a Windows transport path. We standardized the tunnel adapter management to ensure DNS resolution adheres to the VPN tunnel across different Windows transports.
These improvements are incorporated in Colitu's Windows 2.8.4 and Linux 1.4.3 versions, along with fixes from previous updates. The research report, detailing the testing methodology, findings, technical modifications, and testing constraints, is available. Windows testing was carried out on actual devices, while Linux verification utilized automated tests following identical fixture logic.
Mobile platforms were not included in this investigation. We extend our gratitude to @launchgatecheck for suggesting the test scenarios that sparked this analysis. At Colitu, we value open dialogue, as constructive feedback enables us to validate our assumptions, enhance our engineering, and share our findings with the public. To learn more, visit Colitu Lab — Does the connection check really go through the tunnel? and Colitu — Connection Liberty Tunnel.
Written by urgent.news from Dev.to's reporting — not their text. Machine-written — may contain errors; check the original before relying on it.
