[FWD] Re: Greylisting mails with URLs

[hum, did a direct reply instead of a group reply]

Quoting Paul Makepeace ([email protected]):

You obviously were bored today :)  *heheh*

> Roughly: something to tag the email with a "URL/domain of some
> description whatever detected" and then in the GL code look for that
> domain and possibly use that as an additional or parallel GL parameter
> along with envelope and host info.

I filter out stuff on URL by creating my own set of spamassassin rules.
Greylisting as it is now would also filter out this kind of spam, won't
it? 

> Paul

ok, next mail...

Quoting Paul Makepeace ([email protected]):

> I'm sure this is obvious...
> I've noticed spamassassin is writing its various bits to
> /var/spool/exim4/.spamassassin which is Debian-exim's home dir.

True. If not configured to do otherwise.

> How is it getting this? spamd is started and indeed runs as root via
> /etc/init.d/spamassassin. So is it picking up the $HOME via spamc
> called via local_scan in exim?

Exim runs as Debian-exim, local_scal (exim that is) calls spamc, spamc
runs spamassassin as the calling user, and that is Debian-exim, whose
$HOME points to /var/spool/exim4.

>   mkdir /var/lib/spamassassin
>   chown -R Debian-exim:Debian-exim /var/lib/spamassassin

I'm thinking of doing this in my next sa-exim packages. Especially with
greylisting stuff, it's more and more important to have a nice place for
spamassassin / sa-exim related cruft. imho. Nice transition scripts, so
current setups will get converted... hmm.

> Paul

next message!

Quoting Paul Makepeace ([email protected]):

> Actually RTFM I noticed the bayes_ignore_header option:
> Which prompted me to wonder about,
>   bayes_ignore_header X-SA-Exim-Connect-IP
>   bayes_ignore_header X-SA-Exim-Mail-From
>   bayes_ignore_header X-SA-Exim-Rcpt-To
>   bayes_ignore_header X-SA-Exim-Scanned
>   bayes_ignore_header X-SA-Exim-Version

Never cared about those. They always contain the same values, and I
don't think they will actually cause spam to score higher or lower.
Must admit I haven't tried, and I don't think it would HURT adding these
headers in the ignore_header list.

> Paul

ok, next message!

Quoting Paul Makepeace ([email protected]):

> In the hopes this might spark a thread of "here's stuff I did to get
> SA-exim to work more effectively" here is a list of some recent changes
> I've been experimenting with:
> FWIW, I've found the stock SA 2.63 misses sufficiently much spam now
> that the Bayes classifier is autolearning spam, which then feeds back
> and lets even more through. To help against that I used,
>   bayes_auto_learn_threshold_nonspam -0.5
> ..rather than the default of 0.1.

Hmm. I have thought about NOT having SA-exim autolearn ham and spam,
since my system runs on my own personal bayes databases. I have
configured my spamassassin to read /home/ssmeenk/.spamassassin/bayes_*
instead.

I have required hits at 4.0, and reject mail at a score of 8.0. A friend
of mine has his permreject set to 4.0, and no problems, according to
him. I don't want to risk legit mail, since i'm also scanning for some
of the other users on my system, using MY bayes db's..
 
> The extra rules at the SA Rules Emporium have helped a lot too:
> http://www.rulesemporium.com/

Hmm. I only have the 'backhair' set, and then a ever growing set of
self-made rules in which I put rules that trigger on persistant spam
that comes through the normal rules.

> (e.g. the antidrug.cf stuff if you're a meds provider).

I've looked at the antidrug.cf set, that almost resembles my anti drug
set, which filters out a LOT of spam :)

> The SpamCopURI patch to query SURBL is well worth adding as the
> URL/domain is sometimes about the only thing that identifies a
> mail as spam. http://sourceforge.net/projects/spamcopuri

I didn't want to use remote checks, because then my mail delivery would
depend on someone elses ability to keep a stable server, AND my
connection was too slow to handle that back then. I could check it out
now, along with sender / recipient callouts.

> The SA-exim greylisting patch is really great - benefits:
> IMO, if you've been putting off implementing this on your system,
> definitely consider pushing it up the sysadmin TODO list.

I hate patching spamassassin. Marc, any word on upstream implementing
your patches? :)

> Paul

next message!

ah, no next message.
okay then. 

I also drop TONS of mails with my ACL in exim that rejects HELO's with
my own IP. I don't know if you already have that, but i'd recommend it.

Furthermore I noticed that recently more and more spam came through the
filters, but I think this had to do with the Received-header problem,
and me still running sa-exim.
I fear that my bayes db's might have been "poisoned"...

Another question, do you sa-learn? And if so, do you sa-learn ham, spam
or both? I only sa-learn spam. This works for me, but people told me I
should also sa-learn ham...

For now, this is all my text, and i will go fix me some food. :)

Regards,
Sander.
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