It's distribution neutral -- the feature appeared in sendmail 8.12 and
higher.

WARNING: NOT FOR SENDMAIL AMATEURS. If you rely on YaST (or such
programs) to do your system administration, DON'T TRY THIS. Your gun,
your foot, your decision.

Relevant portion of my host.mc local config file (remember to compensate
for word wrap):


dnl
dnl  To stop spamming from known domains and known senders you should
dnl  not use the FEATURE(dialup) nor FEATURE(promiscuous_relay) nor
HACK(nodns).
dnl  To turn on the ability to refuse or allow incoming mail for certain
dnl  recipient usernames, hostnames, or addresses, you should declare
them
dnl  in `/etc/mail/access'.
dnl  You can provide a black list for the FEATURE below list which is
used to
dnl  block incoming mail for certain recipient usernames, hostnames, or
dnl  addresses.
dnl
FEATURE(`blacklist_recipients')dnl
dnl
dnl  The Realtime Blackhole List is a service of rbl.maps.vix.com
dnl  (see http://maps.vix.com/rbl/). It provides a list of hosts
dnl  of known spammers.  The FEATURES below are some other server
dnl  for rejecting well known spammers
dnl  (see http://maps.vix.com/ and http://www.orbs.org/).
dnl
FEATURE(`dnsbl')dnl
FEATURE(`dnsbl',`dul.maps.vix.com',` Mail from $&{client_addr} rejected
- dul; see http://maps.vix.com')dnl
FEATURE(`dnsbl',`relays.osirusoft.com',` Mail from $&{client_addr}
rejected - see http://relays.osirusoft.com')dnl
FEATURE(`dnsbl',`relays.orbs.org', ` Mail from $&{client_addr} rejected
- open relay; see http://www.orbs.org')dnl
FEATURE(`dnsbl',`dun.dnsrbl.net', ` Mail from $&{client_addr} rejected -
dul; see http://www.dnsrbl.com')dnl
FEATURE(`dnsbl',`spam.dnsrbl.net', ` Mail from $&{client_addr} rejected
- known spammer; see http://www.dnsrbl.com')dnl
FEATURE(`dnsbl',`dnsbl.njabl.org',`Message from $&{client_addr} rejected
- see http://njabl.org/')dnl
FEATURE(`dnsbl',`no-more-funn.moensted.dk',` Message from
$&{client_addr} rejected -- see http://no-more-funn.moensted.dk')dnl
dnl
dnl

Insert the lines above into your local sendmail config, m4 it, and put
it online. Note that you'll have to fix word-wrap or you'll get an
unusable .cf file. If you're not using sendmail, see the documentation
for your MTA or do a google search for "dnsbl +yourmailer". I'd
recommend setting up at least a caching name server on the box -- this
increases the number of DNS lookups per mail message substantially, and
it's polite to not beat up on the DNS.

Note that for you folks running SuSE, the linux.mc file shipped in
/etc/mail is NOT the one generated and used by YaST... look at the
script used for SuSEconfig.sendmail or similar to determine what REALLY
gets generated -- you may need to run that script with the -m4 option to
get the actual .mc file used to generate the final .cf file.

This setup eliminates about 90% of the spam attempts we see. Not
perfect, but certainly slows down the less sophisticated bozos.

-- db

David Boyes
Sine Nomine Associates


> -----Original Message-----
> From: Linux on 390 Port [mailto:[EMAIL PROTECTED]]On Behalf Of
> Gregg C Levine
> Sent: Monday, November 25, 2002 2:25 PM
> To: [EMAIL PROTECTED]
> Subject: Re: Admin: can someone put in a reverse DNS for this mail er?
>
>
> Hello from Gregg C Levine
> There, you see Jay, there is a better idea available. David you are
> right. As usual. Especially since I started seeing that
> option available
> for Slackware 7.2 and later. To all of the folks who use Red Hat, and
> even SuSe, do they have that option available? For that
> matter can you,
> David, suggest a few?

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