Network Management and SNMP

1. What is Network Management? ISO Network Management Model(FCAPS) Network Management Architecture SNMPv1 and SNMPv2 SNMPv3 – what’s new? Network Management and SNMP

2. Any complex system with many interacting components must be monitored, managed and controlled In the early 1980 networks expansion prompted the need for automated network management Network Management

3. Network management scenarios • Detecting failure of an interface card in a device • Host monitoring • Traffic monitoring to optimize resource deployment • Detecting rapid changes in routing tables • Intrusion detection

4. FCAPS: Fault management Configuration management Accounting management Performance management Security Management ISO Network Management Model

5. Fault management – log, detect and respond to fault conditions in the network Configuration management – track devices and their h/w and s/w configs Accounting management - specify, log and control user access to network resources Performance management – quantify, measure, report, analyze and control performance of network components Security Management – control access to network resources according to some well-defined policy ISO Network Management Model

6. Network Management Architecture

7. Simple Network Management Protocol • Protocol for network management, part of TCP/IP suite • Current version SNMPv3 • Includes communication protocol, set of data definitions and database schema • Basic components:Managers/NMSManaged devicesSNMP AgentsMIB

8. Was implemented as a full standardin 2004 Only changes relate to security and remote configuration SNMPv3 provides for encryption, authentication and message integrity SNMPv3

9. Network Management Architecture

10. MIB – virtual information store for a collection of managed objects Describes structure of management data on managed device Each variable that describes some part of device configuration is identified by a unique OID (object ID) Vendors define MIB variables for their own use MIB II – standard MIB implemented by all managed objects MIB (Management Information Base)

11. SMI is the language used to define the management information residing in a managed object – logically SMI states that each managed object should have a name, syntax and encoding SMI is a subset of ASN.1 - a standard for describing data that is independent of machine-specific encoding. SMI (Structure of management information)

12. Object naming by OID

13. MIB-II subtree

14. SNMP Transport

15. SNMP Transport

16. get getnext getbulk (SNMPv2 and SNMPv3) set getresponse trap notification (SNMPv2 and SNMPv3) inform (SNMPv2 and SNMPv3) report (SNMPv2 and SNMPv3) SNMP Operations

17. Get and getresponse SNMP Operations

18. Getnext – retreive a group of values SNMP Operations

19. Getbulk – retreive a section of a table SNMP Operations

20. Set – change value or create a new row in the table SNMP Operations

21. Trap – asynchronous operation SNMP Operations

22. Check message integrity - To verify that each received message has not been modified during its transmission . User authentication - To verify the identity of the user on whose behalf a received message claims to have been generated. Message timestamp – to detect outdated messages Message confidentiality - To assure that the contents of each received message are protected/encrypted. Primary Goals of SNMPv3

23. Two core modules within the framework are the User-based Security Model (USM) and the View-based Access Control Model (VACM). The USM is in charge of authenticating/encrypting/decrypting SNMP packets The VACM is in charge of administering access to MIB data. SNMPv3 security framework

24. Authentication -Each SNMP entity is identified by SNMPEngineID, and SNMP communication is possible only if an SNMP entity knows the identity of its peer. Traps and Notifications are exceptions to this rule.Protection against: Modification of Information (Data Integrity)Ensure that the data is not maliciously altered during transit by an unauthorized entity. Masquerading (Data Origin Authentication)Ensure that it is known exactly who and where the data came from to prevent an unauthorized entity from assuming the identity of an authorized user. Disclosure (Data Confidentiality)Ensure that an unauthorized entity cannot eavesdrop on the data exchanges. Message Stream Modification (Message Timeliness)Ensure that the data was received in a timely manner to prevent malicious re-ordering of data by an unauthorized entity. SNMPv3 security framework

25. USM communication mechanisms available: Communication without authentication and privacy (NoAuthNoPriv). Communication with authentication and without privacy (AuthNoPriv). Communication with authentication and privacy (AuthPriv). Different authentication and privacy protocols supported - Currently, the MD5 and SHA authentication protocols and the CBC_DES and CFB_AES_128 privacy protocols are supported in the USM. SNMPv3 User-based Secuirity Model

26. The Access Control Subsystem of an SNMP entity has the responsibility for checking whether a specific type of access to a specific managed object is allowed. Access control occurs in the agent when processing SNMP retrieval or modification request messages from a manager, and also when a notification message must be sent to the manager. Elaborates on the concept of community strings in the previous versions of SNMP SNMPv3 VCAM