From 77689a9aecfba600b6cf1aba7d851f6d78d1ea07 Mon Sep 17 00:00:00 2001
From: Andre <200930841+Andre-Bzk@users.noreply.github.com>
Date: Fri, 23 Oct 2026 09:37:41 +0200
Subject: [PATCH] fix: make tunnel start despite unreadable DNS answers

wstunnel's built-in DNS resolver fails on some DNS servers because it
cannot read their EDNS answers. With a connection pool the client then
never opened the local port. Use the Windows resolver instead.

The port check also took ~2 s per attempt, so the start script showed
an empty window for a long time before the error appeared.
---
 client/scripts/common.ps1 | 9 +++++++--
 1 file changed, 7 insertions(+), 2 deletions(-)

diff --git a/client/scripts/common.ps1 b/client/scripts/common.ps1
index 0b6f10f..8add515 100644
--- a/client/scripts/common.ps1
+++ b/client/scripts/common.ps1
@@ -14,7 +14,11 @@ $LogDir = Join-Path $ClientDir 'logs'
 $ProxyUrl = "http://$LocalProxy"
 
 function Get-TunnelArgs([string]$LogLevel) {
-    $tunnelArgs = @('client', '-L', "http://$LocalProxy", '-c', '2', '--log-lvl', $LogLevel)
+    # Windows-Resolver statt des eingebauten: Manche DNS-Server liefern EDNS-Antworten,
+    # die wstunnel nicht lesen kann. Dann scheitert jede Verbindung, und mit -c wartet
+    # der Client endlos auf den Pool, bevor er den lokalen Port oeffnet.
+    $tunnelArgs = @('client', '-L', "http://$LocalProxy", '-c', '2', '--log-lvl', $LogLevel,
+        '--dns-resolver', 'system://0.0.0.0')
     if (-not $SkipTlsVerify) { $tunnelArgs += '--tls-verify-certificate' }
     if ($UpstreamProxy) { $tunnelArgs += @('--http-proxy', $UpstreamProxy) }
     if ($UpstreamProxyUser) { $tunnelArgs += @('--http-proxy-login', $UpstreamProxyUser) }
@@ -44,7 +48,8 @@ function Invoke-WithTunnelEnv([scriptblock]$Action) {
 function Test-TunnelListening {
     $parts = $LocalProxy.Split(':')
     $client = New-Object System.Net.Sockets.TcpClient
-    try { $client.Connect($parts[0], [int]$parts[1]); return $true }
+    # Connect() auf einen geschlossenen Port dauert unter Windows ~2 s (SYN-Wiederholungen)
+    try { return $client.ConnectAsync($parts[0], [int]$parts[1]).Wait(500) -and $client.Connected }
     catch { return $false }
     finally { $client.Close() }
 }