RE: SNMP Agent engineboot

Dave

Thanks for your help!


>  But when this process re-started, and there is another request comes in,
> SNMP agent will replies error:usmstatus not in timewindow.

That is correct - an SNMPv3 request will fail if the boot time/count
values in the
request don't match the agent's idea of the current values.   I
believe this is to
avoid replay attacks.


> I learnt that SNMP agent should increase the engineboot if agent restarted,
> how should I implement this function that SNMP Manager don't
> need do a handshake again if SNMP agent restarted?

The manager will need to resend the request, with updated boot
count/time values.These can be taken from the "not in timewindow" Report message that was sent by the agent.
   If the manager is written using the Net-SNMP libraries, then I'd expect this to happen automatically.   If it's using a different toolkit, then you'd need to talk to the appropriate vendor to find out how to handle this with their code.

<<<Barclay >>>
I try to use  set_enginetime() by set the engineboots to a value stored in out side of agent.
 set_enginetime(c_engineID, engineIDLen,
                     get_snmpEngineBoots(),
                     snmpv3_local_snmpEngineTime(), TRUE);
Then when Manager side send request, agent will return with new engineboot, then manager side will send request again with new engineboot and time. I thought this time, agent will think its in sync with manager side.
But unfortunately, seems usm_check_and_update_timeliness() will still return error, it will compare the the static engineBoots stored in agent with the new engineboots value. boots_uint != myBoots

        if (boots_uint == ENGINEBOOT_MAX
            || boots_uint != myBoots
            || time_difference > USM_TIME_WINDOW) {
.....
            *error = SNMPERR_USM_NOTINTIMEWINDOW;
            return -1;
        }
myBoots is get from snmpv3_local_snmpEngineBoots:
	snmpv3_local_snmpEngineBoots(void)
	{
   	 	return engineBoots;
	}

Seems I can not set this static engineBoots?
<<<Barclay >>>


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