| 5.4 |  | SNMP |
| 5.4.3 |  | SNMP Version 3 (SNMPv3) |

| SNMPv3 is an interoperable standards-based protocol for network management. SNMPv3 provides secure access to devices by a combination of authenticating and encrypting packets over the network. The security features provided in SNMPv3 are:

- Message integrity—Ensuring that a packet has not been tampered with in-transit.
- Authentication—Determining the message is from a valid source.
- Encryption—Scrambling the contents of a packet prevent it from being seen by an unauthorized source.

SNMPv3 provides for both security models and security levels. A security model is an authentication strategy that is set up for a user and the group in which the user resides. A security level is the permitted level of security within a security model. A combination of a security model and a security level will determine which security mechanism is employed when handling an SNMP packet. Three security models are available: SNMPv1, SNMPv2c, and SNMPv3. Figure identifies what the combinations of security models and levels mean:

The benefits of version 3 include the following:

- Data can be collected securely from SNMP devices without fear of the data being tampered with or corrupted.
- Confidential information, for example, SNMP Set command packets that change a router's configuration, can be encrypted to prevent its contents from being exposed on the network.

Cisco devices such as router and switches support SNMPv3 message types and the increased security capabilities, but many management software applications do not support SNMPv3. Applications which support version 3 include MG-Soft MIB Browser and SNMP Research International’s CiAgent or Enterpol. HP Openview can support version 3 with the help of SNMP Research International extensions.

| Web Links SNMP Link.org http://www.snmplink.org/SNMPv3.html CiscoWorks VPN Solutions Center http://www.cisco.com/en/US/products/
sw/netmgtsw/ps2327/index.html

AdventNet SNMP Utilities
http://www.adventnet.com/products/
snmputilities/index.html

MG-SOFT (supports SNMPv3)
http://www.mg-soft.si/mgMibBrowserPE.html

SNMP Research International
http://www.snmp.com/products/enterpol.html

HP Openview
http://www.openview.hp.com