From 07dbfd8651d1465df780996a696892e642a7186f Mon Sep 17 00:00:00 2001
From: Cloud Wu <cloudwu@gmail.com>
Date: Thu, 28 May 2015 16:18:56 +0800
Subject: [PATCH] add underscore

---
 lualib/dns.lua | 2 +-
 1 file changed, 1 insertion(+), 1 deletion(-)

diff --git a/lualib/dns.lua b/lualib/dns.lua
index 6244b314..35e38084 100644
--- a/lualib/dns.lua
+++ b/lualib/dns.lua
@@ -88,7 +88,7 @@ local function verify_domain_name(name)
 	if #name > MAX_DOMAIN_LEN then
 		return false
 	end
-	if not name:match("^[%l%d-%.]+$") then
+	if not name:match("^[_%l%d%-%.]+$") then
 		return false
 	end
 	for w in name:gmatch("([_%w%-]+)%.?") do