diff --git a/demo/demo b/demo/demo
index 7179ee4d6bedbde38a36bb2c38a3a1d4ca6a035d..e0b900853fd789ad86bca10178bedd18127970e7 100755
--- a/demo/demo
+++ b/demo/demo
@@ -38,6 +38,8 @@ def _add_interface(node, iface):
     return Node__add_interface(node, iface)
 nemu.Node._add_interface = _add_interface
 
+execfile("fixnemu.py")
+
 # create nodes
 for name in """internet=I registry=R
                           gateway1=g1 machine1=1 machine2=2
diff --git a/demo/fixnemu.py b/demo/fixnemu.py
new file mode 100644
index 0000000000000000000000000000000000000000..ab27d927ba80f23533502afe44ff60feaad7eb4e
--- /dev/null
+++ b/demo/fixnemu.py
@@ -0,0 +1,52 @@
+# -*- coding: utf-8 -*-
+
+# Copyright 2010, 2011 INRIA
+# Copyright 2011 Martín Ferrari <martin.ferrari@gmail.com>
+#
+# This file is contains patches to Nemu.
+#
+# Nemu is free software: you can redistribute it and/or modify it under the
+# terms of the GNU General Public License version 2, as published by the Free
+# Software Foundation.
+#
+# Nemu is distributed in the hope that it will be useful, but WITHOUT ANY
+# WARRANTY; without even the implied warranty of MERCHANTABILITY or FITNESS FOR
+# A PARTICULAR PURPOSE.  See the GNU General Public License for more details.
+#
+# You should have received a copy of the GNU General Public License along with
+# Nemu.  If not, see <http://www.gnu.org/licenses/>.
+
+import re
+from nemu.iproute import backticks, get_if_data, get_all_route_data, route
+
+def _get_all_route_data():
+    ipdata = backticks([IP_PATH, "-o", "route", "list"]) # "table", "all"
+    ipdata += backticks([IP_PATH, "-o", "-f", "inet6", "route", "list"])
+
+    ifdata = get_if_data()[1]
+    ret = []
+    for line in ipdata.split("\n"):
+        if line == "":
+            continue
+        match = re.match(r'(?:(unicast|local|broadcast|multicast|throw|' +
+                r'unreachable|prohibit|blackhole|nat) )?' +
+                r'(\S+)(?: via (\S+))? dev (\S+).*(?: metric (\d+))?', line)
+        if not match:
+            raise RuntimeError("Invalid output from `ip route': `%s'" % line)
+        tipe = match.group(1) or "unicast"
+        prefix = match.group(2)
+        nexthop = match.group(3)
+        interface = ifdata[match.group(4)]
+        metric = match.group(5)
+        if prefix == "default" or re.search(r'/0$', prefix):
+            prefix = None
+            prefix_len = 0
+        else:
+            match = re.match(r'([0-9a-f:.]+)(?:/(\d+))?$', prefix)
+            prefix = match.group(1)
+            prefix_len = int(match.group(2) or 32)
+        ret.append(route(tipe, prefix, prefix_len, nexthop, interface.index,
+            metric))
+    return ret
+
+get_all_route_data.func_code = _get_all_route_data.func_code