snmpV3 Trap & Inform issues

[Srini Kode]

Hi,

We are using netsnmp5.1. In this we have observed that V3 Inform and Traps are not working. Below are the details:

We see that for V3 , a probe pdu is sent out for getting the engineID of the remote trap destination for both

INFORM and TRAP. Whereas this is correct for Inform but for TRAP the sender of trap pdu must use

its own engineID and NOT send the probe pdu.

 

TRAP:

We modified the function, notif_snmp_sess_add_ex(...) in snmp_api.c to fix this. We replaced the code:

        if (!snmpv3_engineID_probe(slp, in_session)) {
            DEBUGMSGTL(("snmp_sess_add", "engine ID probe failed\n"));
            snmp_sess_close(slp);
            slp = NULL;

        }

WITH

      if ((slp->session->flags & SNMP_FLAGS_DONT_PROBE) == SNMP_FLAGS_DONT_PROBE) {
           slp->session->securityEngineID = malloc(MAX_ENGINEID_LENGTH);
           slp->session->securityEngineIDLen =

                   snmpv3_get_engineID(slp->session->securityEngineID,MAX_ENGINEID_LENGTH);
       } else {
           if (!snmpv3_engineID_probe(slp, in_session)) {
               DEBUGMSGTL(("snmp_sess_add", "engine ID probe failed\n"));
               snmp_sess_close(slp);
               slp = NULL;
           } 
       }

 

Note that above we maintain a flag SNMP_FLAGS_DONT_PROBE.

 

With this changes now it works for TRAP.

For INFORM we still have a issue.

 

INFORM:

The inform works with only NoAuthNoPriv.

In this case with the probe PDU, we get the user and EngineID of remote trap destination.

But how do we get the authKey and PrivKey of the remote user.

 

Maybe we are missing something. Please let us know your feedback.

 

Thanks

Srini