Modifying default Spamassassin rule scoring

Howdy!

Dealing with a flood of spam each day - and I think I could drastically reduce the volume if I can modify a few rules which seem to be triggered by a majority of the messages.

For example, this is a rule that’s triggered by several of the messages each day:

0.8 RDNS_NONE Delivered to internal network by a host with no rDNS

I’ve looked everywhere for this rule … nothing. I’ve tried adding this rule and custom scoring to my local.cf file … nothing.

Can someone point me in the right direction for modifying rules like this which are shown in the report generated when SA rejects a message?

Grateful,
Justin