AdGuard VPN (WinTun driver) conflicts with other VPN clients using WinTun-based virtual network adapters

[AlexandrPkhm]

AdGuard VPN version

2.9.5 - 2.9.6 (WinTun driver enabled)

Use Wintun

• yes, I do

Issue Details

When AdGuard VPN is used with the WinTun driver enabled, it can conflict with other VPN applications (that also can rely on WinTun in particular). This leads to unstable routing.

Currently confirmed affected VPN clients:

• Check Point VPN
• Radmin VPN
• Tailscale
• OpenVPN clients
• Zapret

Please let us know if your VPN client is affected too.

Steps to reproduce:

1. Install and connect to AdGuard VPN with the WinTun driver enabled.
2. Install and connect to one of the affected VPN clients (Check Point VPN, Radmin VPN, or Tailscale) simultaneously.
3. Attempt to access external resources and monitor which VPN tunnel the traffic actually goes through.

Expected Behavior

AdGuard VPN should either detect the presence of another active WinTun-based VPN adapter and handle routing/DNS gracefully without conflict.

Actual Behavior

When AdGuard VPN (WinTun driver) is active alongside Check Point VPN, Radmin VPN, or Tailscale, routing and DNS resolution become unreliable.

Additional information

If you are not logged into your account, authorization issues may occur if Wintun was initially enabled and a third-party VPN from the list above is installed. In this situation, we recommend disabling the third-party VPN, or uninstalling it if disabling it doesn't help.

[shamarin]

It's an old issue first pointed by me with OpenVPN client 2-3 years ago. Last it was decided to rename AG Wintun. For latest OpenVPN it's not actual due to that Wintun support was removed from 2.7 version.