From fa3af372ab7276ca32f241b3c79d326492126d20 Mon Sep 17 00:00:00 2001
From: Cuong Manh Le <cuong@windscribe.com>
Date: Fri, 14 Jul 2023 15:59:21 +0000
Subject: [PATCH] Use ControlD anycast IP if no system DNS found

---
 resolver.go | 7 +++++++
 1 file changed, 7 insertions(+)

diff --git a/resolver.go b/resolver.go
index f61c9bc..2512434 100644
--- a/resolver.go
+++ b/resolver.go
@@ -29,6 +29,13 @@ const (
 var bootstrapDNS = "76.76.2.0"
 var or = &osResolver{nameservers: nameservers()}
 
+func init() {
+	if len(or.nameservers) == 0 {
+		// Add bootstrap DNS in case we did not find any.
+		or.nameservers = []string{net.JoinHostPort(bootstrapDNS, "53")}
+	}
+}
+
 // Resolver is the interface that wraps the basic DNS operations.
 //
 // Resolve resolves the DNS query, return the result and the corresponding error.