diff --git a/mediaproxy/iputils.py b/mediaproxy/iputils.py
index 808698c..b93c6cd 100644
--- a/mediaproxy/iputils.py
+++ b/mediaproxy/iputils.py
@@ -1,38 +1,42 @@
 # Copyright (C) 2008 AG Projects
 #
 
 """IP address utilities"""
 
 __all__ = ["is_routable_ip"]
 
 import socket
 import struct
+
 from application.configuration.datatypes import NetworkRangeList
 
+
 # Non routable network addresses (RFC 3330)
 #
-_non_routable_netlist = """
-0.0.0.0/8
-10.0.0.0/8
-127.0.0.0/8
-169.254.0.0/16
-172.16.0.0/12
-192.0.2.0/24
-192.168.0.0/16
-224.0.0.0/4
-255.255.255.255/32
-"""
-
-_non_routable_nets = NetworkRangeList(','.join(_non_routable_netlist.strip().split('\n')))
+_non_routable_netlist = [
+    '0.0.0.0/8',
+    '10.0.0.0/8',
+    '127.0.0.0/8',
+    '169.254.0.0/16',
+    '172.16.0.0/12',
+    '192.0.2.0/24',
+    '192.168.0.0/16',
+    '198.51.100.0/24',
+    '203.0.113.0/24',
+    '224.0.0.0/4',
+    '255.255.255.255/32'
+]
+
+_non_routable_nets = NetworkRangeList(_non_routable_netlist)
 
 
 def is_routable_ip(ip):
     try:
         ip_addr = struct.unpack('!L', socket.inet_aton(ip))[0]
     except:
         return False
     for netbase, mask in _non_routable_nets:
         if (ip_addr & mask) == netbase:
             return False
     return True