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Catalyst 6000 Family Software Configuration Guide—Releases 6.3 and 6.4
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Chapter 36 Configuring SNMP
Understanding SNMP
Security Models and 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 determines which security mechanism is employed when handling
an SNMP packet. Three security models are available: SNMPv1, SNMPv2c, and SNMPv3.
Table 36-2
identifies the combinations of security models and defines the levels for SNMPv1, SNMPv2c, and
SNMPv3.
Note the following about SNMPv3 objects:
–
Each user belongs to a group
–
A group defines the access policy for a set of users
–
SNMP objects access an access policy for reading, writing, and creating
–
A group determines the list of notifications its users can receive
–
A group also defines the security model and security level for its users
Table 36-2 SNMP Security Levels
Model
Level
Authentication
Encryption
What Happens
v1
noAuthNoPriv
Community
String
No
Uses a community string
match for authentication.
v2c
noAuthNoPriv
Community
String
No
Uses a community string
match for authentication.
v3
noAuthNoPriv
Username
No
Uses a username match for
authentication.
v3
authNoPriv
MD5 or SHA
No
Provides authentication based
on the HMAC-MD5 or
HMAC-SHA algorithms.
v3
authPriv
MD5 or SHA
DES
Provides authentication based
on the HMAC-MD5 or
HMAC-SHA algorithms.
Provides DES 56-bit
encryption in addition to
authentication based on the
CBC-DES (DES-56) standard.
