FortKnox's Journal: Spamassassin

I just (finally) installed spam assassin on my server (I'm using just straight sendmail, no fanciness, and most accounts are email-aliases/forwards).
I did the CPAN install, and ran (as root):
spamd -ad
Is that it? Will it just filter away now? Is it defaulted to delete any spam or what?

Funny how ignorant I am in spamassassin and email administrating (I'm a coder, not a sysadmin).
Basically, I want it to delete all spam, no need to save it. I need to preserve HD space, as I'm running dangerously low...
Any advice/suggestions?

Don't know about on your own server

[sulli]

but on an ISP service spamassassin kicks ass. I have it running at my ISP and it takes 15-20 messages per day and dumps them into a "Trash" folder - this I review every 3-4 days online via webmail, and in very few cases are false positives found.

Never tried it with Sendmail

[giverson]

I run spamassassin with Qmail at my office. The default install marks spam in the subject and tells in the body of the message why it was spam.

I wouldn't delete all spam by default if I were you. False positives do happen from time to time. You're better off using rules on the client to automatically move tagged mail into a seperate folder.

doesn't delete by default

[ceejayoz]

AFAIK SpamAssassin just tags messages as spam by prepending "***** SPAM *****" to the subject.

I'd recommend against setting it to automatically delete - I get a couple false positives a month.

I've turned off SpamAssassin for a while to teach Mozilla 1.3a my spam preferences... quite nifty, it's tagging almost perfectly now. Can't wait until 1.3 comes out and it actually deletes it in addition to tagging it! :-)

Filtering

[aridhol]

SpamAssassin just tags your emails, it doesn't erease them. It's up to you to change the settings in either Procmail or your reader to handle the headers.

You probably don't want SA to erase your emails. It's good, but it still gets false positives. I have my mailer (Gnus) put all the spams into a separate folder, then go through that folder sometimes. I erase most of them unread, but some are real messages, and I have to put the senders into the whitelist.

Use DNSBLs as well.

[The Turd Report]

Set sendmail to use some of the available DNSBLs. Just tell sendmail to reject them. I use these DNSBLs [bronnenberg.net]. SpamAssasin will clean up what the lists miss.

as others noted

[gmhowell]

As others have noted, it just tags messages. One convenient thing to do is use procmail to look for that tag, and dump it into another maildir.

FWIW, I am happy deleting everything that spamassassin flags.

To delete or not to delete....

[MarkusQ]

My vote on auto deleting: You can (should) tweak the rules that come with spamassasin to suit your situation before you auto delete. What I did:

1. Installed it and edited the message to say something like "The new spam detection software we are testing thinks this is spam. If this message came in a month from now, when we are using the software for real, it would have vanished in a puff of greasy black smoke before you even saw it. If this is a problem, save this message (unchanged) and talk to Markus"
2. As the month went by, I tweaked the rules to give higher scores to things that weren't getting tagged as spam (we have some smart users) and lower the score of things people wanted.
3. At the end of the month, I wrote a script to delete anything that scored over one limit, and then let everything over a second, lower limit go through marked, and changed the message accordingly.
4. At the end of the second month, I had the rules to the point where I could lower the delete limit slightly, raise the marking limit slightly and script those messages off to a holding tank (old messages cleared after 30 days) without worry.

Other notes:

• I added a rule that gave a large negative score to mail, so that people could quote spam in house by including the secret phrase.
• I learned more than I wanted to know about a few of my users. Some of them WANTED things that were, well, spam. I added a few individual rules to accomidate them.
• My biggest problem was one of the sales droids. Everything he wrote seemed to trigger the spam rules, so messages from people responding to his messages (occasionally with things like "leave me alone you moron") would get marked as spam.
  He's no longer with the firm.

-- MarkusQ