 The communication between the network elements (NEs) and the management entity (OSS, operations support system) used to be based on X.25 technology. The knowledge of X.25 is limited to a small population. The security risks were then limited. Today IP technology is widely known and used, and even its standards (RFCs) are open to the general public. CORBA and Java are used for the high-level communication with the nodes. Despite considerable risks of security violations when working in an IP environment, there are not many other options available. The strong technological shift towards the Security Internet for data communication, the increasing maturity of Internet security alternatives and the fact that the connectivity backbone will be based on IP or IP/ATM, force us more or less to use IP for data communication (NE to/from manager) within the manage- ment system. The main communication protocol is simple network management protocol (SNMP). Main security features in SNMPv3 are encryption to assure privacy, and authentication of management-agent communication to guarantee sender identity and message integrity. A solution could look like this: The communication system is built in three layers. A transport IP part, a secure data communication network and an application layer with management support applica- tions. Access is possible only by means of specific logon servers. A public key server is used to generate certificates. The CORBA traffic is secured by means of security modules at application level in the nodes, verifying authority and authenticity. Telnet and FTP traffic are protected by means of SSH/TLS. Security information is stored in a LDAP server. Security for Network Resources Network resources are normally controlled by the management system. As long as the management system is run by authorized staff there is only the human factor that could cause harm to the network through the management system. Making sure that only autho- rized staff can access the management system can be achieved by means of 