Could Be OT: How many people only accept reverse DNS lookupmail?

[Jeff A. Earickson]

On Thu, 17 Aug 2006, Billy A. Pumphrey wrote:

> Date: Thu, 17 Aug 2006 12:45:00 -0400
> From: Billy A. Pumphrey <bpumphrey at WoodMacLaw.com>
> Reply-To: MailScanner discussion <mailscanner at lists.mailscanner.info>
> To: MailScanner discussion <mailscanner at lists.mailscanner.info>
> Subject: RE: Could Be OT: How many people only accept reverse DNS lookupmail?
> 
>> -----Original Message-----
>> From: mailscanner-bounces at lists.mailscanner.info [mailto:mailscanner-
>> bounces at lists.mailscanner.info] On Behalf Of Jeff A. Earickson
>> Sent: Thursday, August 17, 2006 11:53 AM
>> To: MailScanner discussion
>> Subject: RE: Could Be OT: How many people only accept reverse DNS
>> lookupmail?
>>
>> I put require_rdns.m4 back into my sendmail .cf files this morning
>> and turned this back on.  My previous test was on 6/6/2005, over
>> a year ago.  I warned our Helpdesk and I'm waiting for my phone
>> to start screaming...
>>
>> Jeff Earickson
>> Colby College
>>
>
> Will you help me get require_rdns.m4 up and running.  My thoughts so
> far:
>
> Download it at http://www.cs.niu.edu/%7Erickert/cf/hack/require_rdns.m4
> Put it in /etc/mail/spamassassin
> Restart MailScanner
>
> Is this correct?

Nyet!!  The m4 file goes in your sendmail-8.x.x/cf/hack subdirectory.
Then you reference the m4 file in your sendmail.mc file, like so:

HACK(require_rdns,`REJECT')

Then you rebuild your sendmail.cf file from your sendmail.mc file like
so:

M4=/usr/local/bin/m4
CF=/usr/local/src/mail/sendmail/sendmail-8.13.8/cf
$M4 -D_CF_DIR_=${CF}/ ${CF}/m4/cf.m4 sendmail.mc > sendmail.cf

Then you save a copy of your old /etc/mail/sendmail.cf file, put the
new one in place, restart sendmail, and watch your logs to see what
happens.

This whole thing is a sendmail tweak, and has nothing to do with 
MailScanner at all.  Tread carefully, and consult your copy of the
Bat Book.

Jeff Earickson
Colby College