I've seen this before. Perhaps someone knowing the guts of Net::SNMP better than myself could throw more light into this.

Something that has worked quite reliably for me is to destroy and re-create the SNMP object after each error. This is probably not too costly, since creating a UDP socket does not require a connection setup.

The code I use, looks like the following:

sub my_create_snmp {
  my $snmp = ... # Place here the code to create your
                 # SNMP handler.

  return $snmp;
}

...

$response = $session->get_request($cmd);

if (!defined($response)) {
  ...
  $session = my_create_snmp();
  next;
}
[download]

Note however that you must ensure that the required parameters to create a new SNMP session are available to my_create_snmp(). This probably includes global variables or constants. I tend to prefer the later.

Regards.