I am new to writing scripts for discovery and have that down ok... but I am looking for a way to also filter the interfaces if they are not active.

In this case, I have a sonicwall I wish to monitor, but I don't need to see all the ports not in use.  They all show UP because they use PortShields which connect all the ports in an UP fashion, so I wanted to filter on MTU which in SNMP shows zero on all the ports I wish to ignore.

My SNMP DCI looks like this:

Param: .1.3.6.1.2.1.31.1.1.1.10.{instance}
Discovery (OID): .1.3.6.1.2.1.2.2.1.1

Discovery Filter:

transport = CreateSNMPTransport($node);
if (transport == null)
	return false;

// get the interface name to return as instance-name
vb = SNMPGet(transport, ".1.3.6.1.2.1.31.1.1.1.1." . $1);
if (vb == null)
	return false;

// filter out loopback
if (vb->value == "lo")
	return false;

return %(true, $1, vb->value);

I know MTU is pulled in and stored with the interfaces, but not sure how to filter in the discovery script I have so far.

Like I said, pretty new at this and just getting my hands dirty.... so any help would be greatly appreciated!