Simple Network Management Protocol (SNMP) is an application-layer protocol defined by the Internet Architecture Board (IAB) for exchanging management information between network devices. It is a part of Transmission Control Protocol/Internet Protocol (TCP⁄IP) suite.
SNMP is one of the widely accepted protocols to manage and monitor network elements. Most of the professional-grade network elements come with bundled SNMP agent. These agents have to be enabled and configured to communicate with the network management system (NMS). The SNMP agent is a program that resides on your managed device, packaged within the network element. You have to enable it on your device. It collects the management information from the device locally and provides it to the SNMP manager. These agents could be standard, for example, Net-SNMP or specific to a vendor, such as HP Insight Agent.
SNMP uses a password-like authorization known as Community String. When you provide an SNMP credential to a device, it checks to see if the Community String matches to what is configured on the device. If the string matches, the device responds to the SNMP query.
SNMP multi-credential functionality allows you to discover network resources using multiple credentials using a single discovery profile. You can create or use multiple credential sets if you are using a Gateway to discover your resources.
For example, a printer uses SNMPv2c credential type and Cisco router uses SNMPv3 credential type. In such a case, you need to create two discovery profiles. With SNMP multi-credential functionality, you can create one discovery profile and use both the credential sets.
NoteThe gateway discovers the devices with the credentials in a sequential order as entered while creating a Discovery Profile at the time of the first scan. Once the discovery is successful, the gateway remembers the resources and its valid credentials for future discoveries.
The following are the advantages of multi-credentials for SNMP enabled devices:
- Reduces the effort of creating multiple discovery profiles.
- Reduces time for manually traversing through multiple discovery profiles to discover a network resource.
- Scans and discovers a subnet with multiple SNMP community strings.
- Discovers network resources working on different SNMP versions.
SNMP field values
The following provides information on configuring the SNMP fields for creating an SNMP credential set.
SNMPv1 and SNMPv2
|Port||161||Agent receives requests on UDP port 161.|
|Community||N/A||Provide Community string with read-only access.|
SNMPv3 is a user-based security model. It provides secure access to the devices by combining authenticating and encrypting packets over the network. The security features provided in SNMPv3 are message integrity, authentication, and encryption.
|Port||161||SNMP Agent port. The default port is 161.|
|Context||N/A||Specify context name (an octet string) that identifies the collection of management information accessible by an SNMP entity.|
|Security Name||N/A||Provide the name of the user (principal) on whose behalf the message is being exchanged.|
|Authentication Protocol||Authentication in an SNMPv3 uses an encryption algorithm to determine if the data is from a valid source.
The encryption algorithms for authentication:|
|Authentication Password||N/A||Provide the Authentication password.|
|Confirm Password||N/A||Re-enter authentication password for validation.|
|Privacy Protocol||Privacy in SNMPv3 uses an encryption algorithm to encode the contents of an SNMPv3 packet. This encoding is used to verify that the content cannot be viewed by unauthorized entities when routed over the network.|
|Privacy Password||N/A||Provide the privacy password.|
|>Confirm Password||N/A||Re-enter authentication password for validation.|
|Connection time-out||N/A - Default value: 10,000 milliseconds||Provide a maximum time period for discovery. If the Gateway does not receive a response from the device after 10,000 milliseconds, it terminates the discovery.|