Proxy Forwarding and Notification Originators

By default a trap is sent as a notification originator. The difference between acting as a notification originator or acting as a proxy when forwarding the trap is detailed in RFC 2576 “Coexistence Between SNMP Versions”

Proxy Forwarding

Proxy forwarding is activated by calling the forwardAsProxy() method.

When translating SNMPv1 traps into SNMPv2 traps, the varbind received is reused. Three additional varbinds are appended, if these three additional varbinds do not already exist in the SNMPv1 varbinds:

• The name portion of the first additional varbind contains snmpTrapAddress.0, and the value contains the SNMPv1 agent-addr parameter.

• The name portion of the second additional varbind contains snmpTrapCommunity.0, and the value contains the value of the community string field from the received SNMPv1 message which contained the SNMPv1 trap PDU.

• The name portion of the third additional variable binding contains snmpTrapEnterprise.0, and the value is the SNMPv1 enterprise parameter.

The SNMPv1 agent-addr parameter is determined by the proxy extracting the original source of the notification from the varbinds, If the SNMPv2 varbinds contain a varbind whose name is snmpTrapAddress.0, the agent-addr parameter is set to the value of that varbind. Otherwise, the SNMPv1 agent-addr parameter is set to 0.0.0.0.

Notification Originators

Traps are forwarded as notification originators by calling the forwardAsNotificationOriginator() method.

When translating from SNMPv1 to SNMPv2, the SNMPv2 varbinds are the same as the SNMPv1 varbinds.

When translating from SNMPv2 to SNMPv1, the SNMPv1 agent-addr parameter is determined as follow:

• If the notification is sent over IP, the SNMPv1 agent-addr parameter is set to the IP address of the SNMP entity in which the notification originator resides.

• If the notification is sent over some other transport protocol, the SNMPv1 agent-addr parameter is set to 0.0.0.0.