Date: Tue, 14 Apr 1998 10:49:30 -0700 (PDT) From: Dan Busarow <dan@dpcsys.com> Cc: Jeff & Hillary Jones <kf7nn@mutsgo.dyn.ml.org>, questions@FreeBSD.ORG Subject: Re: domain resolve for email Message-ID: <Pine.BSF.3.96.980414104216.3526O-100000@java.dpcsys.com> In-Reply-To: <19980414164844.I1870@freebie.lemis.com>
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On Tue, 14 Apr 1998, Greg Lehey wrote:
> Jeff Jones wrote:
> > I would like to know how to make it so my email accounts
> > do not get mail from unresolveable hosts just like
> > this list.
>
> I'm no longer sure that this is a good idea. Over the last couple of
> days I have set up a mailing list, and I find that a large number of
> legitimate users have transient problems in their reverse lookup (not
> their fault, nor of anybody in their domain). The result is that mail
> to or from them bounces. I've taken mine out as a result.
The "standard" rule for this returns a temporary error so transient
problems shouldn't do more than slow mail from them down.
Here's the one we use
Scheck_mail
# verify valid DNS entry
R$* $: <?> $>3 $1
R<?> $* < @ $+ . > $: <OK>
R<?> $* < @ $+ > $#error $: 451 Domain must resolve $1@$2 $&{client_addr}
I go through the logs checking these once or twice a month. Catches
a huge amount of spam and I've only seen one instance where a legit address
was refused. YMMV
You do need to be aware of the potential problems going in but I think
it is worth it.
Dan
--
Dan Busarow 714 443 4172
DPC Systems / Beach.Net dan@dpcsys.com
Dana Point, California 83 09 EF 59 E0 11 89 B4 8D 09 DB FD E1 DD 0C 82
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