[gentoo-server] Postfix + SNMP = stumped

[Jason Qualkenbush]

I know this isn't a Gentoo specific problem, but since it's a server 
list I'm already subscribed to, I figured I would try here first.

I'm running Postfix and I am trying to get snmp stats (net-snmp) to feed 
cacti (http://www.raxnet.net/products/cacti/).  The best script I found 
that gets the sent and received emails was a set of perl scripts created 
for mrtg called mailstats (http://taz.net.au/postfix/mrtg/). 
Mailstats.pl works just fine.  I modified it so that it should respond 
to snmp.  That's:

----script----
#!/usr/bin/perl

# mailstats.pl
#
# Copyright Craig Sanders 1999
#
# this script is licensed under the terms of the GNU GPL.

use DB_File;

$|=1;

$stats_file = '/tmp/stats.db' ;

tie(%foo, "DB_File", "$stats_file", O_RDONLY, 0666, $DB_HASH) || die 
("Cannot open $stats_file");

foreach (sort keys %foo) {
         if ($_ =~ "RECEIVED:smtp"){
         print ".1.3.6.1.4.1.1021.56.1\n";
         print "counter\n";
         print "$foo{$_}\n" ;
         }else{
         }
} ;
untie %foo;
----end script----

Note: This script runs just fine from the command line. This file is 
called mailstats-r.pl for received mail.

I modified snmpd.conf, and added these lines (.2 is for sent mail):

pass .1.3.6.1.4.1.2021.56.1 /usr/bin/perl /usr/local/sbin/mailstats-r.pl
pass .1.3.6.1.4.1.2021.56.2 /usr/bin/perl /usr/local/sbin/mailstats-s.pl

I should now be able to get my mail stats via snmp, but this is what I 
get instead:

user $ snmpget -v2c -c public mx.domain.tld .1.3.6.1.4.1.2021.56.1
UCD-SNMP-MIB::ucdavis.56.1 = No Such Object available on this agent at 
this OID

I've been all over the snmpd.conf man page, but I just don't get it:
(http://net-snmp.sourceforge.net/man/snmpd.conf.html).

How are people graphing postfix statistics?  I use to use ftp to 
transfer the stats to the cacti server, but I want to use SNMP since 
that's how all the other stats are collected.