diff --git a/ChangeLog b/ChangeLog
index 43f94df275..bd6a257964 100644
--- a/ChangeLog
+++ b/ChangeLog
@@ -1,3 +1,7 @@
+2008-07-07  Dan Williams  <dcbw@redhat.com>
+
+	Convert to using IPv4 prefixes instead of netmasks.
+
 2008-07-03  Dan Williams  <dcbw@redhat.com>
 
 	* libnm-util/nm-setting-ip4-config.c
diff --git a/include/NetworkManagerVPN.h b/include/NetworkManagerVPN.h
index a01b1489b7..8b4c89c6ae 100644
--- a/include/NetworkManagerVPN.h
+++ b/include/NetworkManagerVPN.h
@@ -108,7 +108,7 @@ typedef enum NMVPNConnectionStateReason
 #define NM_VPN_PLUGIN_IP4_CONFIG_GATEWAY "gateway"
 #define NM_VPN_PLUGIN_IP4_CONFIG_ADDRESS "address"
 #define NM_VPN_PLUGIN_IP4_CONFIG_PTP     "ptp"
-#define NM_VPN_PLUGIN_IP4_CONFIG_NETMASK "netmask"
+#define NM_VPN_PLUGIN_IP4_CONFIG_PREFIX  "prefix"
 #define NM_VPN_PLUGIN_IP4_CONFIG_DNS     "dns"
 #define NM_VPN_PLUGIN_IP4_CONFIG_NBNS    "nbns"
 #define NM_VPN_PLUGIN_IP4_CONFIG_MSS     "mss"
diff --git a/introspection/nm-ip4-config.xml b/introspection/nm-ip4-config.xml
index 8e3bf573c1..8ac92a9a1f 100644
--- a/introspection/nm-ip4-config.xml
+++ b/introspection/nm-ip4-config.xml
@@ -3,7 +3,7 @@
 <node name="/" xmlns:tp="http://telepathy.freedesktop.org/wiki/DbusSpec#extensions-v0">
   <interface name="org.freedesktop.NetworkManager.IP4Config">
     <property name="Addresses" type="aau" access="read">
-      <tp:docstring>Tuples of IPv4 address/netmask/gateway.  The gateway is optional, if not given should be 0.</tp:docstring>
+      <tp:docstring>Tuples of IPv4 address/prefix/gateway.  The gateway is optional, if not given should be 0.</tp:docstring>
     </property>
     <property name="Hostname" type="s" access="read">
       <tp:docstring>The hostname associated with this IPv4 address. FIXME: what about multiple hostnames?</tp:docstring>
diff --git a/libnm-glib/libnm-glib-test.c b/libnm-glib/libnm-glib-test.c
index 3d6719203e..80844f4950 100644
--- a/libnm-glib/libnm-glib-test.c
+++ b/libnm-glib/libnm-glib-test.c
@@ -79,8 +79,8 @@ dump_ip4_config (NMIP4Config *cfg)
 		g_print ("IP4 address: %s\n", tmp);
 		g_free (tmp);
 
-		tmp = ip4_address_as_string (addr->netmask);
-		g_print ("IP4 netmask: %s\n", tmp);
+		tmp = ip4_address_as_string (nm_utils_ip4_prefix_to_netmask (addr->prefix));
+		g_print ("IP4 prefix: %d (%s)\n", addr->prefix, tmp);
 		g_free (tmp);
 
 		tmp = ip4_address_as_string (addr->gateway);
diff --git a/libnm-util/nm-setting-ip4-config.c b/libnm-util/nm-setting-ip4-config.c
index a04b70320d..b3f5e6a893 100644
--- a/libnm-util/nm-setting-ip4-config.c
+++ b/libnm-util/nm-setting-ip4-config.c
@@ -70,6 +70,8 @@ static gboolean
 verify (NMSetting *setting, GSList *all_settings, GError **error)
 {
 	NMSettingIP4Config *self = NM_SETTING_IP4_CONFIG (setting);
+	GSList *iter;
+	int i;
 
 	if (!self->method) {
 		g_set_error (error,
@@ -132,6 +134,22 @@ verify (NMSetting *setting, GSList *all_settings, GError **error)
 		return FALSE;
 	}
 
+	/* Validate addresses */
+	for (iter = self->addresses, i = 0; iter; iter = g_slist_next (iter), i++) {
+		NMSettingIP4Address *addr = (NMSettingIP4Address *) iter->data;
+
+		if (!addr->address) {
+			g_warning ("invalid IP4 address #%d", i);
+			return FALSE;
+		}
+
+		if (!addr->prefix || addr->prefix > 32) {
+			g_warning ("invalid IP4 address prefix %d for address #%d",
+			           addr->prefix, i);
+			return FALSE;
+		}
+	}
+
 	return TRUE;
 }
 
diff --git a/libnm-util/nm-setting-ip4-config.h b/libnm-util/nm-setting-ip4-config.h
index ec73d869d3..340662d12b 100644
--- a/libnm-util/nm-setting-ip4-config.h
+++ b/libnm-util/nm-setting-ip4-config.h
@@ -45,16 +45,16 @@ GQuark nm_setting_ip4_config_error_quark (void);
 #define NM_SETTING_IP4_CONFIG_METHOD_SHARED "shared"
 
 typedef struct {
-	guint32 address;
-	guint32 netmask;
-	guint32 gateway;
+	guint32 address;   /* network byte order */
+	guint32 prefix;
+	guint32 gateway;   /* network byte order */
 } NMSettingIP4Address;
 
 typedef struct {
 	NMSetting parent;
 
 	char *method;
-	GArray *dns;        /* array of guint32 */
+	GArray *dns;        /* array of guint32; elements in network byte order */
 	GSList *dns_search; /* list of strings */
 	GSList *addresses;  /* array of NMSettingIP4Address */
 	GSList *routes;     /* array of NMSettingIP4Address */
diff --git a/libnm-util/nm-utils.c b/libnm-util/nm-utils.c
index e23ba361bc..013328d578 100644
--- a/libnm-util/nm-utils.c
+++ b/libnm-util/nm-utils.c
@@ -815,7 +815,7 @@ nm_utils_ip4_addresses_from_gvalue (const GValue *value)
 		
 		addr = g_malloc0 (sizeof (NMSettingIP4Address));
 		addr->address = g_array_index (array, guint32, 0);
-		addr->netmask = g_array_index (array, guint32, 1);
+		addr->prefix = g_array_index (array, guint32, 1);
 		addr->gateway = g_array_index (array, guint32, 2);
 		list = g_slist_prepend (list, addr);
 	}
@@ -838,7 +838,7 @@ nm_utils_ip4_addresses_to_gvalue (GSList *list, GValue *value)
 		array = g_array_sized_new (FALSE, TRUE, sizeof (guint32), 3);
 
 		g_array_append_val (array, addr->address);
-		g_array_append_val (array, addr->netmask);
+		g_array_append_val (array, addr->prefix);
 		g_array_append_val (array, addr->gateway);
 		g_ptr_array_add (addresses, array);
 	}
@@ -846,6 +846,60 @@ nm_utils_ip4_addresses_to_gvalue (GSList *list, GValue *value)
 	g_value_take_boxed (value, addresses);
 }
 
+/*
+ * nm_utils_ip4_netmask_to_prefix
+ *
+ * Figure out the network prefix from a netmask.  Netmask
+ * MUST be in network byte order.
+ *
+ */
+guint32
+nm_utils_ip4_netmask_to_prefix (guint32 netmask)
+{
+	guchar *p, *end;
+	guint32 prefix = 0;
+
+	p = (guchar *) &netmask;
+	end = p + sizeof (guint32);
+
+	while ((*p == 0xFF) && p < end) {
+		prefix += 8;
+		p++;
+	}
+
+	if (p < end) {
+		guchar v = *p;
+
+		while (v) {
+			prefix++;
+			v <<= 1;
+		}
+	}
+
+	return prefix;
+}
+
+/*
+ * nm_utils_ip4_prefix_to_netmask
+ *
+ * Figure out the netmask from a prefix.
+ *
+ */
+guint32
+nm_utils_ip4_prefix_to_netmask (guint32 prefix)
+{
+	guint32 msk = 0x80000000;
+	guint32 netmask = 0;
+
+	while (prefix > 0) {
+		netmask |= msk;
+		msk >>= 1;
+		prefix--;
+	}
+
+	return (guint32) htonl (netmask);
+}
+
 GSList *
 nm_utils_ip6_addresses_from_gvalue (const GValue *value)
 {
diff --git a/libnm-util/nm-utils.h b/libnm-util/nm-utils.h
index f9694b4ec1..e14b616c85 100644
--- a/libnm-util/nm-utils.h
+++ b/libnm-util/nm-utils.h
@@ -180,6 +180,9 @@ gboolean nm_utils_security_valid (NMUtilsSecurityType type,
 GSList *nm_utils_ip4_addresses_from_gvalue (const GValue *value);
 void nm_utils_ip4_addresses_to_gvalue (GSList *list, GValue *value);
 
+guint32 nm_utils_ip4_netmask_to_prefix (guint32 ip4_netmask);
+guint32 nm_utils_ip4_prefix_to_netmask (guint32 ip4_prefix);
+
 GSList *nm_utils_ip6_addresses_from_gvalue (const GValue *value);
 void nm_utils_ip6_addresses_to_gvalue (GSList *list, GValue *value);
 
diff --git a/src/NetworkManagerSystem.c b/src/NetworkManagerSystem.c
index ea5c1b27da..3763b84988 100644
--- a/src/NetworkManagerSystem.c
+++ b/src/NetworkManagerSystem.c
@@ -62,17 +62,17 @@
 #include <netlink/route/link.h>
 
 static gboolean
-route_in_same_subnet (NMIP4Config *config, guint32 dest, guint32 netmask)
+route_in_same_subnet (NMIP4Config *config, guint32 prefix)
 {
 	int num;
 	int i;
 
 	num = nm_ip4_config_get_num_addresses (config);
 	for (i = 0; i < num; i++) {
-		const NMSettingIP4Address *cfg_addr;
+		const NMSettingIP4Address *addr;
 
-		cfg_addr = nm_ip4_config_get_address (config, i);
-		if ((dest & netmask) == (cfg_addr->address & cfg_addr->netmask))
+		addr = nm_ip4_config_get_address (config, i);
+		if (prefix == addr->prefix)
 			return TRUE;
 	}
 
@@ -96,38 +96,11 @@ create_route (int iface_idx, int mss)
 	return route;
 }
 
-static int
-netmask_to_prefix (guint32 netmask)
-{
-	guchar *p;
-	guchar *end;
-	int prefix = 0;
-
-	p = (guchar *) &netmask;
-	end = p + sizeof (guint32);
-
-	while ((*p == 0xFF) && p < end) {
-		prefix += 8;
-		p++;
-	}
-
-	if (p < end) {
-		guchar v = *p;
-
-		while (v) {
-			prefix++;
-			v <<= 1;
-		}
-	}
-
-	return prefix;
-}
-
 static void
 nm_system_device_set_ip4_route (const char *iface, 
 						  NMIP4Config *iface_config,
 						  guint32 ip4_dest,
-						  guint32 ip4_netmask,
+						  guint32 ip4_prefix,
 						  guint32 ip4_gateway,
 						  int mss)
 {
@@ -137,7 +110,7 @@ nm_system_device_set_ip4_route (const char *iface,
 	struct nl_addr *gw_addr = NULL;
 	int err, iface_idx;
 
-	if (iface_config && route_in_same_subnet (iface_config, ip4_dest, ip4_netmask))
+	if (iface_config && route_in_same_subnet (iface_config, ip4_prefix))
 		return;
 
 	nlh = nm_netlink_get_default_handle ();
@@ -152,7 +125,7 @@ nm_system_device_set_ip4_route (const char *iface,
 	/* Destination */
 	dest_addr = nl_addr_build (AF_INET, &ip4_dest, sizeof (ip4_dest));
 	g_return_if_fail (dest_addr != NULL);
-	nl_addr_set_prefixlen (dest_addr, netmask_to_prefix (ip4_netmask));
+	nl_addr_set_prefixlen (dest_addr, (int) ip4_prefix);
 
 	rtnl_route_set_dst (route, dest_addr);
 	nl_addr_put (dest_addr);
@@ -312,7 +285,7 @@ nm_system_device_set_from_ip4_config (const char *iface,
 
 		nm_system_device_set_ip4_route (iface, config, 
 								  route->address,
-								  route->netmask,
+								  route->prefix,
 								  route->gateway,
 								  nm_ip4_config_get_mss (config));
 	}
@@ -366,7 +339,7 @@ nm_system_vpn_device_set_from_ip4_config (NMDevice *active_device,
 			}
 
 			nm_system_device_set_ip4_route (nm_device_get_ip_iface (active_device),
-									  ad_config, vpn_gw, 0xFFFFFFFF, ad_gw,
+									  ad_config, vpn_gw, 32, ad_gw,
 									  nm_ip4_config_get_mss (config));
 		}
 	}
@@ -390,7 +363,7 @@ nm_system_vpn_device_set_from_ip4_config (NMDevice *active_device,
 
 		nm_system_device_set_ip4_route (iface, config,
 								  route->address,
-								  route->netmask,
+								  route->prefix,
 								  route->gateway,
 								  nm_ip4_config_get_mss (config));
 	}
diff --git a/src/NetworkManagerUtils.c b/src/NetworkManagerUtils.c
index 904bf77f77..a4a56448eb 100644
--- a/src/NetworkManagerUtils.c
+++ b/src/NetworkManagerUtils.c
@@ -156,20 +156,54 @@ nm_utils_ip4_addr_to_nl_addr (guint32 ip4_addr)
  * MUST be in network byte order.
  *
  */
-int
-nm_utils_ip4_netmask_to_prefix (guint32 ip4_netmask)
+guint32
+nm_utils_ip4_netmask_to_prefix (guint32 netmask)
 {
-	int i = 1;
+	guchar *p, *end;
+	guint32 prefix = 0;
 
-	g_return_val_if_fail (ip4_netmask != 0, 0);
+	p = (guchar *) &netmask;
+	end = p + sizeof (guint32);
 
-	/* Just count how many bit shifts we need */
-	ip4_netmask = ntohl (ip4_netmask);
-	while (!(ip4_netmask & 0x1) && ++i)
-		ip4_netmask = ip4_netmask >> 1;
-	return (32 - (i-1));
+	while ((*p == 0xFF) && p < end) {
+		prefix += 8;
+		p++;
+	}
+
+	if (p < end) {
+		guchar v = *p;
+
+		while (v) {
+			prefix++;
+			v <<= 1;
+		}
+	}
+
+	return prefix;
 }
 
+/*
+ * nm_utils_ip4_prefix_to_netmask
+ *
+ * Figure out the netmask from a prefix.
+ *
+ */
+guint32
+nm_utils_ip4_prefix_to_netmask (guint32 prefix)
+{
+	guint32 msk = 0x80000000;
+	guint32 netmask = 0;
+
+	while (prefix > 0) {
+		netmask |= msk;
+		msk >>= 1;
+		prefix--;
+	}
+
+	return (guint32) htonl (netmask);
+}
+
+
 /* From hostap, Copyright (c) 2002-2005, Jouni Malinen <jkmaline@cc.hut.fi> */
 
 static int hex2num (char c)
diff --git a/src/NetworkManagerUtils.h b/src/NetworkManagerUtils.h
index e2d024aee5..82f68b72be 100644
--- a/src/NetworkManagerUtils.h
+++ b/src/NetworkManagerUtils.h
@@ -39,8 +39,6 @@ void nm_print_device_capabilities (NMDevice *dev);
 
 struct nl_addr *nm_utils_ip4_addr_to_nl_addr (guint32 ip4_addr);
 
-int nm_utils_ip4_netmask_to_prefix (guint32 ip4_netmask);
-
 char *nm_utils_hexstr2bin (const char *hex, size_t len);
 
 char *nm_ether_ntop (const struct ether_addr *mac);
diff --git a/src/dhcp-manager/nm-dhcp-manager.c b/src/dhcp-manager/nm-dhcp-manager.c
index b69b0dced2..cfcf21612c 100644
--- a/src/dhcp-manager/nm-dhcp-manager.c
+++ b/src/dhcp-manager/nm-dhcp-manager.c
@@ -34,11 +34,11 @@
 #include <errno.h>
 #include <unistd.h>
 #include <fcntl.h>
+#include <stdio.h>
 
 #include "nm-dhcp-manager.h"
 #include "nm-marshal.h"
 #include "nm-utils.h"
-#include "NetworkManagerUtils.h"
 #include "nm-dbus-manager.h"
 #include "nm-dbus-glib-types.h"
 
@@ -1023,8 +1023,8 @@ nm_dhcp_manager_get_ip4_config (NMDHCPManager *manager,
 
 	str = g_hash_table_lookup (device->options, "new_subnet_mask");
 	if (str && (inet_pton (AF_INET, str, &tmp_addr) > 0)) {
-		addr->netmask = tmp_addr.s_addr;
-		nm_info ("  netmask %s", str);
+		addr->prefix = nm_utils_ip4_netmask_to_prefix (tmp_addr.s_addr);
+		nm_info ("  prefix %d (%s)", addr->prefix, str);
 	}
 
 	str = g_hash_table_lookup (device->options, "new_routers");
@@ -1126,7 +1126,7 @@ nm_dhcp_manager_get_ip4_config (NMDHCPManager *manager,
 
 				addr = g_malloc0 (sizeof (NMSettingIP4Address));
 				addr->address = (guint32) rt_addr.s_addr;
-				addr->netmask = 0xFFFFFFFF; /* 255.255.255.255 */
+				addr->prefix = 32; /* 255.255.255.255 */
 				addr->gateway = (guint32) rt_route.s_addr;
 
 				nm_ip4_config_take_static_route (ip4_config, addr);
diff --git a/src/nm-device.c b/src/nm-device.c
index 733897133e..3f50823e56 100644
--- a/src/nm-device.c
+++ b/src/nm-device.c
@@ -648,7 +648,7 @@ nm_device_new_ip4_autoip_config (NMDevice *self)
 	config = nm_ip4_config_new ();
 	addr = g_malloc0 (sizeof (NMSettingIP4Address));
 	addr->address = (guint32) ip.s_addr;
-	addr->netmask = (guint32) ntohl (0xFFFF0000);
+	addr->prefix = 16;
 	nm_ip4_config_take_address (config, addr);
 
 	return config;
@@ -699,7 +699,7 @@ nm_device_new_ip4_shared_config (NMDevice *self)
 	config = nm_ip4_config_new ();
 	addr = g_malloc0 (sizeof (NMSettingIP4Address));
 	addr->address = tmp_addr;
-	addr->netmask = (guint32) ntohl (0xFFFFFF00); /* 255.255.255.0 */
+	addr->prefix = 24; /* 255.255.255.0 */
 	nm_ip4_config_take_address (config, addr);
 
 	/* Remove the address lock when the object gets disposed */
diff --git a/src/nm-ip4-config.c b/src/nm-ip4-config.c
index 17d0e1a533..40acfc364a 100644
--- a/src/nm-ip4-config.c
+++ b/src/nm-ip4-config.c
@@ -490,13 +490,6 @@ static int ip4_addr_to_rtnl_peer (guint32 ip4_address, struct rtnl_addr *addr)
 	return err;
 }
 
-static void ip4_addr_to_rtnl_prefixlen (guint32 ip4_netmask, struct rtnl_addr *addr)
-{
-	g_return_if_fail (addr != NULL);
-
-	rtnl_addr_set_prefixlen (addr, nm_utils_ip4_netmask_to_prefix (ip4_netmask));
-}
-
 static int ip4_addr_to_rtnl_broadcast (guint32 ip4_broadcast, struct rtnl_addr *addr)
 {
 	struct nl_addr	* local = NULL;
@@ -534,14 +527,15 @@ nm_ip4_config_to_rtnl_addr (NMIP4Config *config, guint32 i, guint32 flags)
 	if (flags & NM_RTNL_ADDR_PTP_ADDR)
 		success = (ip4_addr_to_rtnl_peer (priv->ptp_address, addr) >= 0);
 
-	if (flags & NM_RTNL_ADDR_NETMASK)
-		ip4_addr_to_rtnl_prefixlen (config_addr->netmask, addr);
+	if (flags & NM_RTNL_ADDR_PREFIX)
+		rtnl_addr_set_prefixlen (addr, config_addr->prefix);
 
 	if (flags & NM_RTNL_ADDR_BROADCAST) {
-		guint32 hostmask, network, bcast;
+		guint32 hostmask, network, bcast, netmask;
 
-		network = ntohl (config_addr->address) & ntohl (config_addr->netmask);
-		hostmask = ~ntohl (config_addr->netmask);
+		netmask = nm_utils_ip4_prefix_to_netmask (config_addr->prefix);
+		network = ntohl (config_addr->address) & ntohl (netmask);
+		hostmask = ~ntohl (netmask);
 		bcast = htonl (network | hostmask);
 
 		success = (ip4_addr_to_rtnl_broadcast (bcast, addr) >= 0);
@@ -597,7 +591,7 @@ ip4_addresses_to_gvalue (GSList *list, GValue *value)
 		array = g_array_sized_new (FALSE, TRUE, sizeof (guint32), 3);
 
 		g_array_append_val (array, ip4_addr->address);
-		g_array_append_val (array, ip4_addr->netmask);
+		g_array_append_val (array, ip4_addr->prefix);
 
 		if (ip4_addr->gateway)
 			g_array_append_val (array, ip4_addr->gateway);
diff --git a/src/nm-ip4-config.h b/src/nm-ip4-config.h
index 95af877fea..e071dd8e96 100644
--- a/src/nm-ip4-config.h
+++ b/src/nm-ip4-config.h
@@ -107,11 +107,11 @@ void			nm_ip4_config_set_mss			(NMIP4Config *config, guint32 mss);
 #define NM_RTNL_ADDR_NONE		0x0000
 #define NM_RTNL_ADDR_ADDR		0x0001
 #define NM_RTNL_ADDR_PTP_ADDR		0x0002
-#define NM_RTNL_ADDR_NETMASK		0x0004
+#define NM_RTNL_ADDR_PREFIX		0x0004
 #define NM_RTNL_ADDR_BROADCAST	0x0008
 
-#define NM_RTNL_ADDR_DEFAULT		(NM_RTNL_ADDR_ADDR | NM_RTNL_ADDR_NETMASK | NM_RTNL_ADDR_BROADCAST)
-#define NM_RTNL_ADDR_PTP_DEFAULT	(NM_RTNL_ADDR_ADDR | NM_RTNL_ADDR_NETMASK | NM_RTNL_ADDR_PTP_ADDR)
+#define NM_RTNL_ADDR_DEFAULT		(NM_RTNL_ADDR_ADDR | NM_RTNL_ADDR_PREFIX | NM_RTNL_ADDR_BROADCAST)
+#define NM_RTNL_ADDR_PTP_DEFAULT	(NM_RTNL_ADDR_ADDR | NM_RTNL_ADDR_PREFIX | NM_RTNL_ADDR_PTP_ADDR)
 
 struct rtnl_addr *nm_ip4_config_to_rtnl_addr (NMIP4Config *config, guint32 i, guint32 flags);
 
diff --git a/src/ppp-manager/nm-ppp-manager.c b/src/ppp-manager/nm-ppp-manager.c
index 6a7258e7fb..2dfe3e8122 100644
--- a/src/ppp-manager/nm-ppp-manager.c
+++ b/src/ppp-manager/nm-ppp-manager.c
@@ -339,12 +339,9 @@ impl_ppp_manager_set_ip4_config (NMPPPManager *manager,
 
 	remove_timeout_handler (manager);
 
-	/* FIXME */
-/* 	g_source_remove (priv->ipconfig_timeout); */
-/* 	priv->ipconfig_timeout = 0; */
-
 	config = nm_ip4_config_new ();
 	addr = g_malloc0 (sizeof (NMSettingIP4Address));
+	addr->prefix = 32;
 
 	val = (GValue *) g_hash_table_lookup (config_hash, NM_PPP_IP4_CONFIG_GATEWAY);
 	if (val) {
@@ -356,18 +353,14 @@ impl_ppp_manager_set_ip4_config (NMPPPManager *manager,
 	if (val)
 		addr->address = g_value_get_uint (val);
 
-	val = (GValue *) g_hash_table_lookup (config_hash, NM_PPP_IP4_CONFIG_NETMASK);
+	val = (GValue *) g_hash_table_lookup (config_hash, NM_PPP_IP4_CONFIG_PREFIX);
 	if (val)
-		addr->netmask = g_value_get_uint (val);
-	else {
-		/* If no netmask, default to Class C address */
-		addr->netmask = htonl (0x000000FF);
-	}
+		addr->prefix = g_value_get_uint (val);
 
-	if (addr->netmask && addr->address) {
+	if (addr->address && addr->prefix) {
 		nm_ip4_config_take_address (config, addr);
 	} else {
-		nm_warning ("%s: invalid IPv4 address or netmask received!", __func__);
+		nm_warning ("%s: invalid IPv4 address received!", __func__);
 		g_free (addr);
 		goto out;
 	}
diff --git a/src/ppp-manager/nm-pppd-plugin.c b/src/ppp-manager/nm-pppd-plugin.c
index c4e2071b2a..3df478ddb3 100644
--- a/src/ppp-manager/nm-pppd-plugin.c
+++ b/src/ppp-manager/nm-pppd-plugin.c
@@ -15,6 +15,7 @@
 #include "nm-ppp-status.h"
 #include "nm-pppd-plugin-glue.h"
 #include "nm-dbus-glib-types.h"
+#include "nm-utils.h"
 
 int plugin_init (void);
 
@@ -163,8 +164,7 @@ nm_ip_up (void *data, int arg)
 						 uint_to_gvalue (peer_opts.hisaddr));
 	}
 
-	g_hash_table_insert (hash, NM_PPP_IP4_CONFIG_NETMASK, 
-					 uint_to_gvalue (0xFFFFFFFF));
+	g_hash_table_insert (hash, NM_PPP_IP4_CONFIG_PREFIX, uint_to_gvalue (32));
 
 	if (opts.dnsaddr[0] || opts.dnsaddr[1]) {
 		array = g_array_new (FALSE, FALSE, sizeof (guint32));
diff --git a/src/ppp-manager/nm-pppd-plugin.h b/src/ppp-manager/nm-pppd-plugin.h
index a06b947ab9..9899641406 100644
--- a/src/ppp-manager/nm-pppd-plugin.h
+++ b/src/ppp-manager/nm-pppd-plugin.h
@@ -4,7 +4,7 @@
 
 #define NM_PPP_IP4_CONFIG_INTERFACE "interface"
 #define NM_PPP_IP4_CONFIG_ADDRESS "address"
-#define NM_PPP_IP4_CONFIG_NETMASK "netmask"
+#define NM_PPP_IP4_CONFIG_PREFIX "prefix"
 #define NM_PPP_IP4_CONFIG_GATEWAY "gateway"
 #define NM_PPP_IP4_CONFIG_DNS "dns"
 #define NM_PPP_IP4_CONFIG_WINS "wins"
diff --git a/src/vpn-manager/nm-vpn-connection.c b/src/vpn-manager/nm-vpn-connection.c
index 50f8540ede..9758bfd234 100644
--- a/src/vpn-manager/nm-vpn-connection.c
+++ b/src/vpn-manager/nm-vpn-connection.c
@@ -290,7 +290,7 @@ print_vpn_config (NMIP4Config *config,
 	nm_info ("VPN Gateway: %s", ip_address_to_string (addr->gateway));
 	nm_info ("Tunnel Device: %s", tundev);
 	nm_info ("Internal IP4 Address: %s", ip_address_to_string (addr->address));
-	nm_info ("Internal IP4 Netmask: %s", ip_address_to_string (addr->netmask));
+	nm_info ("Internal IP4 Prefix: %d", addr->prefix);
 	nm_info ("Internal IP4 Point-to-Point Address: %s",
 		    ip_address_to_string (nm_ip4_config_get_ptp_address (config)));
 	nm_info ("Maximum Segment Size (MSS): %d", nm_ip4_config_get_mss (config));
@@ -298,9 +298,9 @@ print_vpn_config (NMIP4Config *config,
 	num = nm_ip4_config_get_num_static_routes (config);
 	for (i = 0; i < num; i++) {
 		addr = nm_ip4_config_get_static_route (config, i);
-		nm_info ("Static Route: %s/%s Gateway: %s",
+		nm_info ("Static Route: %s/%d Gateway: %s",
 			    ip_address_to_string (addr->address),
-			    ip_address_to_string (addr->netmask),
+			    addr->prefix,
 			    ip_address_to_string (addr->gateway));
 	}
 
@@ -344,7 +344,7 @@ merge_vpn_routes (NMVPNConnection *connection, NMIP4Config *config)
 
 		errno = 0;
 		prefix = strtol (p + 1, NULL, 10);
-		if (errno || prefix < 0 || prefix > 32) {
+		if (errno || prefix <= 0 || prefix > 32) {
 			nm_warning ("Ignoring invalid route '%s'", route);
 			goto next;
 		}
@@ -356,7 +356,7 @@ merge_vpn_routes (NMVPNConnection *connection, NMIP4Config *config)
 
 			addr = g_new0 (NMSettingIP4Address, 1);
 			addr->address = tmp.s_addr;
-			addr->netmask = ntohl (0xFFFFFFFF << (32 - prefix));
+			addr->prefix = (guint32) prefix;
 			addr->gateway = 0;
 
 			nm_ip4_config_take_static_route (config, addr);
@@ -390,6 +390,7 @@ nm_vpn_connection_ip4_config_get (DBusGProxy *proxy,
 	config = nm_ip4_config_new ();
 
 	addr = g_malloc0 (sizeof (NMSettingIP4Address));
+	addr->prefix = 24; /* default to class C */
 
 	val = (GValue *) g_hash_table_lookup (config_hash, NM_VPN_PLUGIN_IP4_CONFIG_GATEWAY);
 	if (val)
@@ -403,15 +404,11 @@ nm_vpn_connection_ip4_config_get (DBusGProxy *proxy,
 	if (val)
 		nm_ip4_config_set_ptp_address (config, g_value_get_uint (val));
 
-	val = (GValue *) g_hash_table_lookup (config_hash, NM_VPN_PLUGIN_IP4_CONFIG_NETMASK);
+	val = (GValue *) g_hash_table_lookup (config_hash, NM_VPN_PLUGIN_IP4_CONFIG_PREFIX);
 	if (val)
-		addr->netmask = g_value_get_uint (val);
-	else {
-		/* If no netmask, default to Class C address */
-		addr->netmask = htonl (0x000000FF);
-	}
+		addr->prefix = g_value_get_uint (val);
 
-	if (addr->address && addr->netmask) {
+	if (addr->address && addr->prefix) {
 		nm_ip4_config_take_address (config, addr);
 	} else {
 		g_warning ("%s: invalid IP4 config received!", __func__);
diff --git a/system-settings/plugins/ifcfg-fedora/reader.c b/system-settings/plugins/ifcfg-fedora/reader.c
index fdf1404b39..aef49f5a8b 100644
--- a/system-settings/plugins/ifcfg-fedora/reader.c
+++ b/system-settings/plugins/ifcfg-fedora/reader.c
@@ -164,6 +164,7 @@ make_ip4_setting (shvarFile *ifcfg, GError **error)
 	char *value = NULL;
 	NMSettingIP4Address tmp = { 0, 0, 0 };
 	char *method = NM_SETTING_IP4_CONFIG_METHOD_MANUAL;
+	guint32 netmask = 0;
 
 	value = svGetValue (ifcfg, "BOOTPROTO");
 	if (value && (!g_ascii_strcasecmp (value, "bootp") || !g_ascii_strcasecmp (value, "dhcp")))
@@ -195,14 +196,15 @@ make_ip4_setting (shvarFile *ifcfg, GError **error)
 		}
 	}
 
-	get_one_ip4_addr (ifcfg, "NETMASK", &tmp.netmask, error);
+	get_one_ip4_addr (ifcfg, "NETMASK", &netmask, error);
 	if (*error)
 		goto error;
+	tmp.prefix = nm_utils_ip4_netmask_to_prefix (netmask);
 
 done:
 	s_ip4 = (NMSettingIP4Config *) nm_setting_ip4_config_new ();
 	s_ip4->method = g_strdup (method);
-	if (tmp.address || tmp.netmask || tmp.gateway) {
+	if (tmp.address || tmp.prefix || tmp.gateway) {
 		NMSettingIP4Address *addr;
 		addr = g_new0 (NMSettingIP4Address, 1);
 		memcpy (addr, &tmp, sizeof (NMSettingIP4Address));
diff --git a/system-settings/plugins/ifcfg-suse/parser.c b/system-settings/plugins/ifcfg-suse/parser.c
index 65db38d89c..1f1ee4b4bf 100644
--- a/system-settings/plugins/ifcfg-suse/parser.c
+++ b/system-settings/plugins/ifcfg-suse/parser.c
@@ -95,20 +95,6 @@ make_connection_setting (shvarFile *file,
 	return (NMSetting *) s_con;
 }
 
-static guint32
-ip4_prefix_to_netmask (int prefix)
-{
-	guint32 msk = 0x80000000;
-	guint32 netmask = 0;
-
-	while (prefix > 0) {
-		netmask |= msk;
-		msk >>= 1;
-		prefix--;
-	}
-
-	return htonl (netmask);
-}
 
 static NMSetting *
 make_ip4_setting (shvarFile *ifcfg)
@@ -145,7 +131,7 @@ make_ip4_setting (shvarFile *ifcfg)
 			tmp.address = ip4_addr.s_addr;
 
 			if (g_strv_length (pieces) == 2)
-				tmp.netmask = ip4_prefix_to_netmask (atoi (pieces[1]));
+				tmp.prefix = atoi (pieces[1]);
 		} else
 			g_warning ("Ignoring invalid IP4 address '%s'", str);
 
@@ -153,31 +139,37 @@ make_ip4_setting (shvarFile *ifcfg)
 		g_free (str);
 	}
 
-	if (tmp.address && tmp.netmask == 0) {
+	if (tmp.address && tmp.prefix == 0) {
 		str = svGetValue (ifcfg, "PREFIXLEN");
 		if (str) {
-			tmp.netmask = ip4_prefix_to_netmask (atoi (str));
+			tmp.prefix = atoi (str);
 			g_free (str);
 		}
 	}
 
-	if (tmp.address && tmp.netmask == 0) {
+	if (tmp.address && tmp.prefix == 0) {
 		str = svGetValue (ifcfg, "NETMASK");
 		if (str) {
 			struct in_addr mask_addr;
 
 			if (inet_pton (AF_INET, str, &mask_addr) > 0)
-				tmp.netmask = mask_addr.s_addr;
+				tmp.prefix = nm_utils_ip4_netmask_to_prefix (mask_addr.s_addr);
 			else {
 				g_warning ("Ignoring invalid IP4 addres: invalid netmask: '%s'", str);
 				tmp.address = 0;
-				tmp.netmask = 0;
+				tmp.prefix = 0;
 			}
 			g_free (str);
 		}
 	}
 
-	if (tmp.address || tmp.netmask) {
+	if (!tmp.prefix || tmp.prefix > 32) {
+		g_warning ("Ignoring invalid IP4 addres: invalid prefix: '%d'", tmp.prefix);
+		tmp.address = 0;
+		tmp.prefix = 0;
+	}
+
+	if (tmp.address) {
 		NMSettingIP4Address *addr;
 		addr = g_new0 (NMSettingIP4Address, 1);
 		memcpy (addr, &tmp, sizeof (NMSettingIP4Address));
diff --git a/system-settings/plugins/keyfile/reader.c b/system-settings/plugins/keyfile/reader.c
index 0aa7be7d77..72a2ed81a3 100644
--- a/system-settings/plugins/keyfile/reader.c
+++ b/system-settings/plugins/keyfile/reader.c
@@ -1,5 +1,7 @@
 /* -*- Mode: C; tab-width: 5; indent-tabs-mode: t; c-basic-offset: 5 -*- */
 
+#include <errno.h>
+#include <stdlib.h>
 #include <sys/stat.h>
 #include <unistd.h>
 #include <sys/types.h>
@@ -88,6 +90,7 @@ read_array_of_array_of_uint (GKeyFile *file,
 		int ret;
 		GArray *address;
 		guint32 empty = 0;
+		int j;
 
 		key_name = g_strdup_printf ("address%d", i);
 		tmp = g_key_file_get_string_list (file, setting->name, key_name, &length, NULL);
@@ -103,17 +106,33 @@ read_array_of_array_of_uint (GKeyFile *file,
 
 		/* convert the string array into IP addresses */
 		address = g_array_sized_new (FALSE, TRUE, sizeof (guint32), 3);
-		for (iter = tmp; *iter; iter++) {
+		for (iter = tmp, j = 0; *iter; iter++, j++) {
 			struct in_addr addr;
 
-			ret = inet_pton (AF_INET, *iter, &addr);
-			if (ret <= 0) {
-				g_warning ("%s: ignoring invalid IPv4 %s element '%s'", __func__, key_name, *iter);
-				g_array_free (address, TRUE);
-				goto next;
-			}
+			if (j == 1) {
+				/* prefix */
+				long tmp_prefix;
+				guint32 prefix;
 
-			g_array_append_val (address, addr.s_addr);
+				errno = 0;
+				tmp_prefix = strtol (*iter, NULL, 10);
+				if (errno || (tmp_prefix < 0) || (tmp_prefix > 32)) {
+					g_warning ("%s: ignoring invalid IPv4 %s prefix '%s'", __func__, key_name, *iter);
+					g_array_free (address, TRUE);
+					goto next;
+				}
+				prefix = (guint32) tmp_prefix;
+				g_array_append_val (address, prefix);
+			} else {
+				/* address and gateway */
+				ret = inet_pton (AF_INET, *iter, &addr);
+				if (ret <= 0) {
+					g_warning ("%s: ignoring invalid IPv4 %s element '%s'", __func__, key_name, *iter);
+					g_array_free (address, TRUE);
+					goto next;
+				}
+				g_array_append_val (address, addr.s_addr);
+			}
 		}
 
 		/* fill in blank gateway if not specified */
diff --git a/test/nm-tool.c b/test/nm-tool.c
index 47d73d6b15..4e3dee922d 100644
--- a/test/nm-tool.c
+++ b/test/nm-tool.c
@@ -339,13 +339,16 @@ detail_device (gpointer data, gpointer user_data)
 
 		for (iter = (GSList *) nm_ip4_config_get_addresses (cfg); iter; iter = g_slist_next (iter)) {
 			NMSettingIP4Address *addr = iter->data;
+			char *tmp2;
 
 			tmp = ip4_address_as_string (addr->address);
 			print_string ("  Address", tmp);
 			g_free (tmp);
 
-			tmp = ip4_address_as_string (addr->netmask);
-			print_string ("  Netmask", tmp);
+			tmp2 = ip4_address_as_string (nm_utils_ip4_prefix_to_netmask (addr->prefix));
+			tmp = g_strdup_printf ("%d (%s)", addr->prefix, tmp2);
+			g_free (tmp2);
+			print_string ("  Prefix", tmp);
 			g_free (tmp);
 
 			tmp = ip4_address_as_string (addr->gateway);