Specifications

Traps and Informs
SNMP Notification messages (Traps and Informs) provide the mechanism for one SNMP application to notify
another SNMP application that something has occurred or been noticed. The SNMPv3 protocol mandates that
all notification message be rejected unless the SNMPv3 user sending the notification already exists in the
remote SNMP agent's user database. The user database in an SNMPv3 application is actually referenced by a
combination of the user's name (Security Name) and an identifier for the given SNMP application (engineID).
Console's snmptrapd Configuration window lets you configure the Security User credentials and/or Engine
IDs for devices from which Console's SNMPTrap Service (snmptrapd) will accept SNMPv3 Notification
messages. If this information is not provided as part of the SNMPTrap Service configuration, all Notification
messages are dropped by SNMPTrap Service. They do not appear in the Console's Trap/Event log and they
are not acknowledged by SNMPTrap Service.
SNMPv3 traps and SNMPv3 inform messages differ in operation. When two SNMP agents communicate, one
agent is always designated as authoritative. This authoritative designation depends on the type of message.
When an SNMP message expects a response (e.g., SNMPv3 Inform), then the receiver is authoritative. When
an SNMP message does not expect a response (e.g., SNMPv3 Trap), then the sender is authoritative. This is
important because it is the authoritative agent's EngineID together with a Security User Name that must be
recognized before the receiver will accept the message.
SNMPv3 Traps
Traps are one−way notification messages. They are not acknowledged by a receiving SNMP application. The
Security User and Engine ID of the sending agent is included in SNMPv3 trap messages. So, before trap
messages can be received in Console, the SNMPTrap Service needs to know both the Security User
credentials and the engine ID of the sending SNMP agent.
Because of this, you must define the Security User credentials and engineID of the SNMP agents for every
device from which you want to receive SNMPv3 traps. This information is defined using the
createUser
directive in the
snmptrapd.conf
file. So, if you want to have 100 SNMP agents send SNMPv3 traps to the
SNMPTrap Service, you need 100
createUser
directives (defining both the security user credentials and
engine ids) in the configuration file.
createUser
Example for Traps:
createUser −e 0x01:02:03:04:05:A1:B2:C3:D4:E5 myUser MD5 myauthpassword DES myprivpassword
Where:
−e <engine:id> specifies the engineID of the sending agent
Traps and Informs 252