diff --git a/DynDNS/dyndns.lua b/DynDNS/dyndns.lua
index d615752..14a1b4c 100644
--- a/DynDNS/dyndns.lua
+++ b/DynDNS/dyndns.lua
@@ -1,4 +1,4 @@
--- Configuration
+-- Configuration Start
 
 local lookup_dhcp_leases = true
 local dhcp_leases_file = "/tmp/dhcp.leases"
@@ -7,19 +7,24 @@ local lookup_ip_neigh = true
 
 local non_fqdn = true
 local network_domain = ".lan"
+local whitelisted_networks = {"192.168.0.0/16", "172.16.0.0/12", "10.0.0.0/8", "fd00::/8"}
 
 local output_file = "/tmp/dyndns"
 
 local reload_command = "/etc/init.d/dnsmasq reload"
 
+-- Configuration End
+
+
+local ip = require("ip")
 
 function split(inputstr, sep)
 	if sep == nil then
-			sep = "%s"
+		sep = "%s"
 	end
-	local t={}
+	local t = {}
 	for str in string.gmatch(inputstr, "([^"..sep.."]+)") do
-			table.insert(t, str)
+		table.insert(t, str)
 	end
 	return t
 end
@@ -38,25 +43,22 @@ function contains(tab, val)
     return false
 end
 
-function ipv4(ip)
-    local chunks = {ip:match("(%d+)%.(%d+)%.(%d+)%.(%d+)")}
-    if (#chunks == 4) then
-        for _,v in pairs(chunks) do
-            if (tonumber(v) < 0 or tonumber(v) > 255) then
-                return false
-            end
-        end
-        return true
-    else
-        return false
-    end
+whitelisted_networks_v4 = {}
+whitelisted_networks_v6 = {}
+for index, value in ipairs(whitelisted_networks) do
+	local parsed_ip = ip.parse(value)
+	local ip_kind = parsed_ip:kind()
+	if ip_kind == "ipv4" then table.insert(whitelisted_networks_v4, parsed_ip) end
+	if ip_kind == "ipv6" then table.insert(whitelisted_networks_v6, parsed_ip) end
 end
 
-function ipv6(ip)
-	local _, chunks = ip:gsub("[%a%d]+%:?", "")
-    if chunks == 8 then
-        return true
-    end
+function ip_match(parsed_ip)
+	local ip_kind = parsed_ip:kind()
+	if ip_kind == "ipv4" then whitelisted_list = whitelisted_networks_v4 end
+	if ip_kind == "ipv6" then whitelisted_list = whitelisted_networks_v6 end
+	for index, value in ipairs(whitelisted_list) do
+		if parsed_ip:match(value) then return true end
+	end
 	return false
 end
 
@@ -80,8 +82,8 @@ function pairs_by_keys(t, f)
         table.insert(a, n)
     end
     table.sort(a, f)
-    local i = 0      -- iterator variable
-    local iter = function ()   -- iterator function
+    local i = 0
+    local iter = function ()
         i = i + 1
         if a[i] == nil then
             return nil
@@ -117,7 +119,7 @@ function compare_tables(a,b)
 end
 
 
-array = {}
+local array = {}
 
 if lookup_dhcp_leases then
 
@@ -125,7 +127,7 @@ if lookup_dhcp_leases then
 	local dhcp_table = split(dhcp_file:read('*all'), "\r\n")
 	dhcp_file:close()
 
-	for key,value in pairs(dhcp_table) do
+	for key, value in pairs(dhcp_table) do
 		local dhcp_lease = split(value, " ")
 		local mac = dhcp_lease[2]
 		if not array[mac] then
@@ -145,7 +147,7 @@ if lookup_ip_neigh then
 	local neigh_table = split(neigh_file:read('*all'), "\r\n")
 	neigh_file:close()
 
-	for key,value in pairs(neigh_table) do
+	for key, value in pairs(neigh_table) do
 		local neigh = split(value, " ")
 		local mac = neigh[5]
 		local ip = neigh[1]
@@ -161,30 +163,32 @@ if lookup_ip_neigh then
 
 end
 
-config = ""
+local config = ""
 
-for key,value in pairs(array) do
-	local mac = key
-	local ip = value["ip"]
+for i1, value in pairs(array) do
+	local ip_list = value["ip"]
 	local hostname = value["hostname"]
 	if hostname ~= "?" and hostname ~= "*" then
-		for key,value in pairs(ip) do
-			line = value
-			if non_fqdn then line = line .. " " .. hostname end
-			if network_domain then line = line .. " " .. (hostname .. network_domain) end
-			if line ~= value then config = config .. "\r\n" .. line end
+		for i2, ip_addr in pairs(ip_list) do
+			parsed_ip = ip.parse(ip_addr)
+			if ip_match(parsed_ip) then
+				local line = ip_addr
+				if non_fqdn then line = line .. " " .. hostname end
+				if network_domain then line = line .. " " .. (hostname .. network_domain) end
+				if line ~= ip_addr then config = config .. "\r\n" .. line end
+			end
 		end
 	end
 end
 
-config_file = read_file(output_file)
+local config_file = read_file(output_file)
 if config_file == nil then config_file = "" end
 
-c1 = sort_table(split(config_file, "\r\n"))
-c2 = sort_table(split(config, "\r\n"))
+local c1 = sort_table(split(config_file, "\r\n"))
+local c2 = sort_table(split(config, "\r\n"))
 
 if not compare_tables(c1, c2) then
-	file = io.open(output_file, "w")
+	local file = io.open(output_file, "w")
 	file:write(config)
 	file:close()
 	os.execute(reload_command)