The trap forwarder daemon receives a trap on a specified port and forwards it to multiple ports on the same host and on different hosts. This allows multiple SNMP managers at one IP address to be able to receive all of the traps sent to one port.
When traps are forwarded, the originating IP address on the forwarded datagram will be that of the trap forwarder daemon, not the originating agent. SNMPv1 format traps are not typically a problem; the trap PDU contains the IP address of the originating agent. However, SNMPv2 format traps do not contain the agent's IP address. For SNMPv2 format traps, the trap forwarder daemon can be configured to append the originating agent's IP address to the datagram that gets forwarded. The receiving management application must have logic to obtain the agent's IP address from the end of the datagram. The default is to pass the datagram that was received without adding anything to it.
For the trap forwarder daemon to forward the datagram with the agent address, the ADD_RECV_FROM_INFO option must be coded on the destination address line in the TRAPFWD.CONF configuration file. See the z/OS Communications Server: IP Configuration Reference for statement syntax. The receiving management application must parse the received datagram, along with the appended agent address. The address field contains the originating agent address, followed by the length of the address. By examining the last four bytes of the received datagram, the management application can determine the length of the agent address.