diff --git a/tobiko.conf.example b/tobiko.conf.example
index d713b8e26..09283d316 100644
--- a/tobiko.conf.example
+++ b/tobiko.conf.example
@@ -108,7 +108,7 @@
 #ipv4_prefixlen = 24
 
 # The CIDR block to allocate IPv6 subnets from (string value)
-#ipv6_cidr = 2003::/48
+#ipv6_cidr = 2001:db8::/48
 
 # The mask bits for IPv6 subnets (integer value)
 #ipv6_prefixlen = 64
diff --git a/tobiko/openstack/neutron/config.py b/tobiko/openstack/neutron/config.py
index 5ea01544d..88175cf08 100644
--- a/tobiko/openstack/neutron/config.py
+++ b/tobiko/openstack/neutron/config.py
@@ -28,7 +28,7 @@ OPTIONS = [
                default=24,
                help="The mask bits for IPv4 subnets"),
     cfg.StrOpt('ipv6_cidr',
-               default='2003::/48',
+               default='2001:db8::/48',
                help="The CIDR block to allocate IPv6 subnets from"),
     cfg.IntOpt('ipv6_prefixlen',
                default=64,