There could be several possibilities. check to make sure DNS, NIS and hosts contain the same names associated with the IP address. check if the device has multiple ip addresses. if so, make sure that one of the interfaces is not being diabled and enabled. Are you looking at the label or actual hostname in NNM? If the label is changing that is somethin different. set the variable IP_NO_SYMBOL_CHANGES=TRUE or modify the ipmap registration file.