Simple Network Management Protocol (SNMP) Traps enable an SNMP agent to notify the SNMP management system upon detection of significant changes occurring locally on the managed host. These are carried out by way of an unsolicited SNMP message.

SNMP Traps are network packets or message fragments containing data related to the component of the system sending the trap. The data may be status related or statistical in nature.

They can also be alerts created by agents on a managed device. These SNMP traps generate 5 types of data:

  • Coldstart or Warmstart;
  • Linkup or Linkdown;
  • egpNeighborloss;
  • Enterprise specific; and
  • Authentication fails.

How SNMP Traps are Generated

SNMP traps are created when the right conditions have been met on the SNMP agent. These conditions are described in the Management Information Base (MIB) being offered by the vendor.

The SNMP management system then defines the limits to the conditions in creating the trap. These can vary from preset thresholds to a restart.

After the conditions have been met, the SNMP agent then forms an SNMP packet that indicates the following fields:

  • SNMP Version can either be SNMPv1 or SNMPv2.
  • Community means the Community name of the SNMP agent.
  • Enterprise identifies the type of managed object, whether corporation or organization, that generates the trap.
  • Agent Address provides the IP address of the SNMP agent that generates the trap.
  • Generic Trap Type indicates one of the generic trap types such as Cold Start, Link Up, Enterprise, etc.
  • Specific Trap Code indicates one of the specific trap codes. When Generic is set to Enterprise, a specific trap ID is identified.
  • Timestamp provides the amount of time that has elapsed between the generation of the trap and the last network reinitialization.
  • Variable bindings are the data field of the trap that contains PDU.
  • Object x Value x is the the current value and the Object Identifier (OID) of the trap.

Where Can SNMP Traps be Applied?

SNMP Traps can be applied to the following Microsoft Windows systems:

  • Microsoft Windows 95;
  • Microsoft Windows NT Workstation 4.0 Developer Edition;
  • Microsoft Windows NT Workstation 3.1;
  • Microsoft Windows NT Server 3.5;
  • Microsoft Windows NT Workstation 3.5;
  • Microsoft Windows NT Advanced Server 3.1;
  • Microsoft Windows NT Server 3.51;
  • Microsoft Windows NT Server 4.0 Standard Edition; and
  • Microsoft Windows NT Workstation 3.51.