On Tue, Nov 20, 2001 at 12:34:12PM -0500, Matthew G. Saroff wrote:
Hi,
My ISP has instituted an ORBS-type (actually ORBZ)
filtering system, which dumps everything that comes from
bad IPs. They have Procmail installed as an MDA.
As I deal with thousands of potential email contacts,
this means that I could miss emails are legitimately intended
for me (I typically see about a 3% false positive rate).
Is there a way at the system level to allow individual
users to opt out?
Your ISP will have to remove the MTA-based ORBZ blocking in order for
any mail to hit your procmail recipes.
Note that having procmail do dnsbl processing will cause a MUCH heavier
load on your ISP's mail server than having the filters in the MTA, and
your ISP may not like that.
I am assuming that one could test for the presense of a
file that a user could put in his home directory before dumping
this stuff to /dev/null, but I would not know how to implement
this on a system wide .procmailrc file?
What would be the technique? I'm assuming that it would
be something like this:
:0h:
! ? test -r $HOME/.deleteorbs
[a script using nslookup or a regularly updated list of IP numbers]
Check out http://www.waltdnes.org for some good recipes for reversing a
dotted quad. With those recipes, if you just want to toss the mail, you
could probably do something like:
:0h
* ! ? test -f $HOME/.markorbz
* ! ? host ${REVERSED}.outputs.orbz.org >/dev/null 2>/dev/null
/dev/null
This would obviously require a 'host' command which would return(0) on
a successful lookup and return something else on a failure. The 'host'
command in FreeBSD does this; YMMV.
Also check out Catherine Hampton's http://www.spambouncer.org/.
--
Paul Chvostek
<paul(_at_)it(_dot_)ca>
Operations / Development / Abuse / Whatever vox: +1 416 598-0000
IT Canada http://www.it.ca/
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