[SNMP4J] SnmpV3 timeout issue with system clock drift

[Jochen Katz]

Hi,

> You'll notice that everything is polling ok at a 10s interval until
> there is a time drift at 2011-11-04 19:32:38,500, from this point on,
> all the snmp results return null, which I assume are timeouts. Looking
> at the logs, it appears that the request should return a "Not in time
> window" exception. Also, the pcap does show a pdu report of
> "1.3.6.1.6.3.15.1.1.2.0"  for the not in time window exception. Let me
> know if you need further information or see something that I'm doing
> wrong. I'll see if I can debug further as well.

so now I can see the reason: While on the agent side only 10 seconds
have passed, your desktop time increases from 19:21:38,317 to
19:32:38,500 (11 minutes!). So SNMP4j drops all responses of the agent,
as these are 11 minutes old, which is more than the 150 seconds time window.

Sorry, but SNMPv3 standard does not allow to resynchronize the engine
time in this case.

My suggestion would be: Create a new thread that continuously sleeps for
five seconds and checks if this time drift has happend. If there was a
time drift, clear the complete time table.