[ILUG] sendmail and filters

[Paul Jakma]

On Wed, 30 Jan 2002, Barry Redmond wrote:

> The junk mail comes from different sources because it's being 
> "returned" from non-existant destination addresses.  The return 
> address is always a real address (different each time) on one of our 
> systems, but with 6 apparently random digits appended to the 
> username.  Is there any *easy* way to insert a filter that can apply a 
> regular expression to parts of a header as the mail is coming in, and 
> give a reject/accept decision?  

if you look in the headers, are they using the same server to relay 
the mail to you each time? if so, with sendmail 8.11 you can put:

Connect:<ip-addr>	REJECT

if not, you could use a global /etc/procmailrc and have a filter to 
direct 'user([0-9]){6}@mydom.foo' to /dev/null.

> I already use a realtime blackhole list, and block some specific junk 
> addresses, but this case needs a finer mechanism.

we use:

	inputs.orbz.org
	relays.ordb.org
	Spamsites.relays.OsiruSoft.com
	spamhaus.relays.OsiruSoft.com
	spews.relays.OsiruSoft.com

which blocks out a lot of spam.

> Thanks,
> Barry Redmond

--paulj