Bounce Queue full

My compliments to kdent for his excellent postqueue FAQ.

I am running whatever postfix runs on RedHat 9
(rpm reports postfix-1.1.12-1).

I've been trying to piece together what I should do for a situation where
I am seeing numerous NDN's from spam that are 'sticking' in the active
queue for long periods of time (which causes legitimate mail being
forwarded to also get stuck as 'active' for an hour or more).

When I examine my queue sizes, I see this (du -k):
22672 ./active
1060 ./bounce
15896 ./defer
31312 ./deferred
1100 ./incoming
4 ./maildrop

The bounce queue is very small. It's like these NDN messages are either
sticking in 'active' status, or they are being treated as regular
messages and 'deferred'.

I've added to my main.cf the parameter,
bounce_queue_lifetime = 6000s
Which in theory should drop NDN's after 100 minutes.
But I don't know if my Postfix is recent enough to use this parameter.
Would it give an error message if it did not?
I'll set the above to a more reasonable figure once the 'crush' is off.

But with so little in the 'bounce' queue, will the above parameter do what
it says? I cannot find entries in my logs that show the original mails
incoming to know if I have a specific 'source' for this heavy load.
All I see are bunches of queued mail from <>.

One last question: I am using procmail as my local delivery agent.
Can I use the 'local_recipient_maps' parameter safely to block
mail? I have alias_maps and NIS unix password system.
The FAQ was not quite clear on this....

Thanks!

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