A bit OT: Cut off address probes?

[Furnish, Trever G]

/me wonders what version of sendmail the BadRcptThrottle setting appeared
in, since it doesn't seem to be present in my m4/mc/cf files. :-(

> -----Original Message-----
> From: Ken Anderson [mailto:ka at PACIFIC.NET]
> Sent: Monday, August 04, 2003 6:23 PM
> To: MAILSCANNER at JISCMAIL.AC.UK
> Subject: Re: A bit OT: Cut off address probes?
>
>
> Furnish, Trever G wrote:
>
> > This is probably a bit off-topic, and I hope it's not a faq
> somewhere
> > already - feel free to yell at me constructively if so. :-)
> >
> > Is there a way to configure sendmail (or whatever) such
> that "address
> > probes" are less effective and intrusive?  I could imagine
> how the process
> > might work, but I've never coded a milter and am hoping
> someone else has
> > done this or will tell me why it would be a bad idea.
> >
> > By address probe, I mean connections that either:
> >         1. Ask the receiving mta to accept a message for
> one invalid address
> > after another despite repeated negative responses from the
> receiving mta.
> > Something that amounts to "Is bob valid?" ... "no"  ...
> "Well, what about
> > tom?"  ... "no"  ... "Frank?" ... etc.
>
> See
> http://www.sendmail.org/m4/tweaking_config.html#confBAD_RCPT_THROTTLE
>
> >         2. Send a message with many recipients at the same
> server, learning
> > those that don't bounce.
> >
> > Completely blocking "no such user" responses seems like a
> bad idea, but
> > ignoring someone who attempted delivery to X number of
> invalid addresses
> > within Y seconds seems like a good idea.  But how can the
> first-line MTA
> > know whether or not an address is invalid?
>
> You have to tell it.
> Use access db with blacklist recipients.
> See:
> http://www.sendmail.org/m4/features.html#blacklist_recipients
> Ken
>
> > Has anyone set up or read of such a system?  Perhaps a
> sendmail milter that
> > looks up recipient addresses in a flat file or via ldap
> before accepting the
> > message?
> >
> > --
> > Trever
> >
> >
>