From ef4c63812bb750893cb009eed78d157aa2900689 Mon Sep 17 00:00:00 2001
From: yuhan6665 <1588741+yuhan6665@users.noreply.github.com>
Date: Tue, 12 Oct 2021 11:32:45 -0400
Subject: [PATCH] Fix: nullcheck on alternative systemDialer (#752)

* fix: null-check on alternative systemDialer
* delete deprecated option DualStack

Co-authored-by: rurirei <72071920+rurirei@users.noreply.github.com>
---
 transport/internet/system_dialer.go | 3 +--
 1 file changed, 1 insertion(+), 2 deletions(-)

diff --git a/transport/internet/system_dialer.go b/transport/internet/system_dialer.go
index 8a0fb89a..9932300b 100644
--- a/transport/internet/system_dialer.go
+++ b/transport/internet/system_dialer.go
@@ -74,7 +74,6 @@ func (d *DefaultSystemDialer) Dial(ctx context.Context, src net.Address, dest ne
 
 	dialer := &net.Dialer{
 		Timeout:   time.Second * 16,
-		DualStack: true,
 		LocalAddr: resolveSrcAddr(dest.Network, src),
 	}
 
@@ -174,7 +173,7 @@ func (v *SimpleSystemDialer) Dial(ctx context.Context, src net.Address, dest net
 // xray:api:stable
 func UseAlternativeSystemDialer(dialer SystemDialer) {
 	if dialer == nil {
-		effectiveSystemDialer = &DefaultSystemDialer{}
+		dialer = &DefaultSystemDialer{}
 	}
 	effectiveSystemDialer = dialer
 }