[PLUG] Mail Administration Question [ANSWERED]

[Keith Lofstrom]

On Mon, Apr 06, 2015 at 09:48:53AM -0700, Rich Shepard wrote:
> On Mon, 6 Apr 2015, John Meissen wrote:
> 
> >In my personal opinion, yes. 90% of the spam I reject is based on no
> >reverse-DNS being available. My assumption is that any legitimate server
> >will have properly configured reverse-DNS configured.
> 
>   Thanks, John. That's good enough for me.

So - how do you configure Spamassassin to do that? 

---- Details ----

In my case, mail passes through another machine (A) before it
hits the machine (B) with Spamassassin running on it. 

[Internet]
   -> [machine A: Outer Mail Router
        runs Postfix with postgrey
        runs some Mailman mailing lists (no spam so far)
        runs my websites
        minimal memory and disk space, but 10Gbps FAST
      ]
      -> [machine B: Inner Mail Host
            Spamassassin runs here
            mail accounts 
              personal white/black lists
              personal spam buckets
         ]

It would be Really Inconvenient to run Spamassassin on machine A,
but how does B know about the IP address that mail came from?  Or
is B concerned only with valid reverse DNS (to whatever IP address)
for the domain name in the message header?

I get about 200 spams a day in the spam bucket, 20 spams make it
through to users, and about one valid but not-yet-whitelisted
email a week goes into the bucket. 

On machine A, using iptables, I blocked half a dozen IP address
blocks in China, which got rid of half the spam and 90% of the
website attacks.

Keith

-- 
Keith Lofstrom          keithl at keithl.com