Junk mail filtering only working on internal mail (and only some of them)

Question

Good morning
I'm trying to get Junk Mail filtering working properly on my server (currently running 10.5.6). All mail that comes from externally doesn't seem to pass through the spam filter at all. It gets scanned for viruses (in the email header i get "X-Virus-Scanned: amavisd-new at example.co.uk" but no sign of any spam filtering.
I have previously configured the filtering using the instructions here http://www.netmojo.ca/blog/2009/04/13/spam-proofing-leopard-server/ but i had been searching through the support here and had started following the instructions in the OS X mail manual, creating a junkmail user and forwarding email to it. Whilst doing this i noticed that some emails had started to be tagged as junk using the settings i had set in server admin. These have something like the following in the email header:
X-Virus-Scanned: amavisd-new at example.co.uk
X-Spam-Flag: YES
X-Spam-Score: 3.479
X-Spam-Level: *
X-Spam-Status: Yes, score=3.479 tagged_above=2 required=2
tests=[ALL_TRUSTED=-1.44, AWL=0.286, HTML_MESSAGE=0.001,
RAZOR2CF_RANGE_51100=0.5, RAZOR2CF_RANGE_E8_51100=1.5,
RAZOR2_CHECK=0.5, URIBLOBSURBL=2.132]
However those emails not tagged as spam do not have any such lines. I would have expected to see X-Spam-Flag: NO and the spam score and such. Are these lines hidden if a mail does not trigger the threshold?
I've had this aparently learning for about a week now and even with the setting set on 1 it's still yet to catch a single piece of junk mail entering into the server.
I do have emails to quite a few different domains directed to this server so i added the lines suggested here http://discussions.apple.com/thread.jspa?messageID=7034527&#7034527 to /etc/amavisd.conf but to no avail.
Any suggestions? Any parts of any log files that may be of use? I've been looking at the junk mail log in debug mode in SA and also in terminal but there's so many lines per mail it's difficult to see what's going on. I can't see anything different from one mail to the next...
Thanks

Answer 1

I would have expected to see X-Spam-Flag: NO and the spam score and such. Are these lines hidden if a mail does not trigger the threshold.
You need to edit /etc/amavisd.conf and set:
$satag_leveldeflt = -999;
This will make sure all mails get the headers inserted.
Also make sure that "@bypassspam_checksmaps = (1); " is commented out.
That said, the Bayesian filter will need to be fed at least 200 HAM and 200 SPAM messages before it kicks in.
Each time you modify settings in amavisd.conf, you need to restart amavisd by issuing:
sudo /bin/launchctl unload /System/Library/LaunchDaemons/org.amavis.amavisd.plist
sudo /bin/launchctl load /System/Library/LaunchDaemons/org.amavis.amavisd.plist
HTH,
Alex
P.S. When you make changes in Postfix' configuration files, simply issue "sudo postfix reload" to make the m stick. No need to stop Postfix (BTW: That article you linked to is full of inaccuracies).