Dell PowerConnect 5548 User Guide - Page 308

• Privacy - Protects against disclosure of message content. Cipher BlockChaining (CBC) is used for encryption. Either authentication alone can be enabled on an SNMP message, or both authentication and privacy can be enabled on an SNMP message. However privacy cannot be enabled without authentication. • Timeliness - Protects against message delay or message redundancy. The SNMP agent compares incoming message to the message time information. • Key Management - Defines key generation, updates, and use. The switch supports SNMP notification filters, based on Object IDs (OIDs), which are used by the system to manage switch features. Authentication or Privacy Keys are modified in the User Security Model (USM). SNMPv3 can only be enabled if the Local Engine ID is enabled. SNMP Access Rights Access rights in SNMP are managed in the following ways: • SNMPv1 and SNMPv2 - Communities The community name is a password sent by the SNMP management station to the device for authentication purposes. A community string is transmitted along with the SNMPv1,v2 frames, but neither the frames nor the community string are encrypted. Since SNMPv1 and SNMPv2 are not encrypted, they are not secure. Communities can be associated with views or groups, and they are defined in the Community pages. • SNMPv3 - Users and Groups SNMP v3 works with users instead of communities. The users belong to groups that have access rights assigned to them. Users are defined in the User Security Model pages SNMPv3 provides two security mechanisms: - Authentication - The switch checks that the SNMP user is an authorized system administrator. This is done for each and every frame. 308 Dell PowerConnect 55xx Systems User Guide