Application Development Software

I am running iPlanet 5.2p1 on a Windows 2000 Server, the system is currently working but I still need toconfigure mail filtering and as such have the following questions.
I am trying to filter inbound e-mail from UBE by using

1) mailfromdnsverify flag of the imta to deny e-mail from ip addresses which I can't do a validaing domain lookup on.
2) Use of extrnal RBL lists, through edits to the "mappings.conf" file.

The edits I added to enable these features are listed below. Bold designates inserted type.

=========================================
Mappings file section edits to add RBL
Filtering
=========================================
PORT_ACCESS

*|*|*|*|* $C$|INTERNAL_IP;$3|$Y$E
! Next line is an RBL Blocking of SPAM attempt
TCP|*|25|*|*|$C$[D:\Server5\bin\msg\imta\lib\dns_verify.dll ,dns_verify_domain_port,$1,dnsbl.sorbs.net,Your$ host$ ($1)$ found$ on$ dnsblock$ list]$E
TCP|*|25|*|*|$C$[D:\Server5\bin\msg\imta\lib\dns_verify.dll ,dns_verify_domain_port,$1,bl.spamcop.net,Your$ host$ ($1)$ found$ on$ dnsblock$ list]$E
* $YEXTERNAL
========================================


========================================
imta.cnf section edits listed
========================================
!
! tcp_local
tcp_local mailfromdnsverify smtp mx single_sys remotehost inner switchchannel identnonelimited subdirs 20 maxjobs 7 pool SMTP_POOL maytlsserver maysaslserver saslswitchchannel tcp_auth
tcp-daemon
================= end of editted sections =======================

After making these changes and running imsimta refresh I have the following problems.

1) I'm not sure if these edits are active, I don't see any log entries indicating that either the rule was run and passed, or the rule ran and failed. Is the format of my changes have to do with wether the action is logged or not.

2) I also don't if the mailfromdnsverify flag is working (or I see no logging of this filtering event either way).

As far as the mailfromdnsverify flag, there was a similar question posted on the forum in 2002 which was never replied to.

A lot of forum messages mention SpamAssassin and Brightmail, but few address setting up RBLs, RBL are my first choice, please help on RBLs.

Thank you in advance for your help.

--Anthony