diff --git a/src/settings/plugins/ifcfg-rh/nms-ifcfg-rh-writer.c b/src/settings/plugins/ifcfg-rh/nms-ifcfg-rh-writer.c
index a670ba5d1e..c6957e8816 100644
--- a/src/settings/plugins/ifcfg-rh/nms-ifcfg-rh-writer.c
+++ b/src/settings/plugins/ifcfg-rh/nms-ifcfg-rh-writer.c
@@ -2102,6 +2102,7 @@ write_ip4_setting (NMConnection *connection, shvarFile *ifcfg, GError **error)
 	 */
 	for (i = n = 0; i < num; i++) {
 		NMIPAddress *addr;
+		guint prefix;
 
 		addr = nm_setting_ip_config_get_address (s_ip4, i);
 
@@ -2131,9 +2132,18 @@ write_ip4_setting (NMConnection *connection, shvarFile *ifcfg, GError **error)
 		}
 
 		svSetValueStr (ifcfg, addr_key, nm_ip_address_get_address (addr));
-		svSetValueInt64 (ifcfg, prefix_key, nm_ip_address_get_prefix (addr));
 
-		svUnsetValue (ifcfg, netmask_key);
+		prefix = nm_ip_address_get_prefix (addr);
+		svSetValueInt64 (ifcfg, prefix_key, prefix);
+
+		/* If the legacy "NETMASK" is present, keep it. */
+		if (svGetValue (ifcfg, netmask_key, &tmp)) {
+			char buf[INET_ADDRSTRLEN];
+
+			g_free (tmp);
+			svSetValueStr (ifcfg, netmask_key, nm_utils_inet4_ntop (prefix, buf));
+		}
+
 		svUnsetValue (ifcfg, gw_key);
 		n++;
 	}