diff --git a/lib/cmdlib.py b/lib/cmdlib.py
index 9fde736b483529ce0ccbb366bac03944d59d2122..a85996ee9c9a1a6ff6e451688c4e8d99fa9632e5 100644
--- a/lib/cmdlib.py
+++ b/lib/cmdlib.py
@@ -7003,9 +7003,8 @@ class LUCreateInstance(LogicalUnit):
                                      errors.ECODE_INVAL)
         nic_ip = self.hostname1.ip
       else:
-        if not netutils.IP4Address.IsValid(ip):
-          raise errors.OpPrereqError("Given IP address '%s' doesn't look"
-                                     " like a valid IP" % ip,
+        if not netutils.IPAddress.IsValid(ip):
+          raise errors.OpPrereqError("Invalid IP address '%s'" % ip,
                                      errors.ECODE_INVAL)
         nic_ip = ip
 
@@ -8678,7 +8677,7 @@ class LUSetInstanceParams(LogicalUnit):
         if nic_ip.lower() == constants.VALUE_NONE:
           nic_dict['ip'] = None
         else:
-          if not netutils.IP4Address.IsValid(nic_ip):
+          if not netutils.IPAddress.IsValid(nic_ip):
             raise errors.OpPrereqError("Invalid IP address '%s'" % nic_ip,
                                        errors.ECODE_INVAL)