Date: Wed, 17 Apr 2002 14:41:31 +1200 From: Jonathan Chen <jonc@chen.org.nz> To: Giorgos Keramidas <keramida@ceid.upatras.gr> Cc: Sam <sam@wa4phy.net>, questions@FreeBSD.ORG Subject: Re: rc.firewall rules help Message-ID: <20020417144131.B62542@grimoire.chen.org.nz> In-Reply-To: <20020417012021.GA28097@hades.hell.gr>; from keramida@ceid.upatras.gr on Wed, Apr 17, 2002 at 04:20:21AM %2B0300 References: <3CBC6847.5D03116B@vortex.wa4phy.net> <20020417012021.GA28097@hades.hell.gr>
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On Wed, Apr 17, 2002 at 04:20:21AM +0300, Giorgos Keramidas wrote:
> On 2002-04-16 14:07, Sam wrote:
> > Can someone give me some hints how to stop connections from spambots by
> > refusing smtp or tcp connections from hosts who won't resolve via
> > reverse lookup, or even forward lookup? Is the firewall script the
> > appropriate place to put that, or would somewhere within sendmail be
> > more better?
>
> Sendmail by default does that already. You need to explicitly disable
> it, by using either one or both of:
>
> FEATURE(`accept_unqualified_senders')dnl
> FEATURE(`accept_unresolvable_domains')dnl
That's not true. Sendmail will accept connections from unresolvable
domains (I've got the email to prove this). By default, it will not
accept email with a unresolveable MAIL FROM: during the conversation.
The last option listed above disables this check.
To disable connections from unresolvable domains requires extending the
Local_relay_check rule within the mc file. Exactly just what needs to
be put in is a mystery to me - I don't grok the syntax.
--
Jonathan Chen <jonc@chen.org.nz>
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