Vicious Circle

[Steen, Glenn]

> -----Original Message-----
> From: MailScanner mailing list 
> [mailto:MAILSCANNER at JISCMAIL.AC.UK] On Behalf Of Martin Hepworth
> Sent: den 7 mars 2005 14:42
> To: MAILSCANNER at JISCMAIL.AC.UK
> Subject: Re: Vicious Circle
> 
> 
> Dave Goodrich wrote:
> > Steen, Glenn wrote:
> >
> >>> -----Original Message-----
> >>> From: MailScanner mailing list
> >>> [mailto:MAILSCANNER at JISCMAIL.AC.UK] On Behalf Of Dave Goodrich
> >>> Sent: den 5 mars 2005 18:10
> >>> To: MAILSCANNER at JISCMAIL.AC.UK
> >>> Subject: Vicious Circle
> >>>
> >>
> >> (snip)
> >>
> >>> I am at a loss, the root of the issue is I have 100k 
> messages a day,
> >>> some just *might* be legitimate address misspellings, I 
> can't drop all
> >>> bounces. But the vast majority are trash.
> >>
> >>
> >>
> >> I think you have a "fault" in your reasoning here. The 
> responsibility
> >> (and thus requirement to produce bounces) for a message is 
> not yours
> >> until after you've accepted the message. So if you do, as 
> many here have
> >> already recommended, reject (with a 550) any unknown 
> recipients/domains,
> >> then the resposibility to generate a NDN/NDR would still 
> be _the sending
> >> MTAs problem, not yours_.
> >
> >
> > Ahh, I understand now, but if I reject with a 550, won't 
> that cause my
> > MailScanner box to then generate the bounce back to the 
> original server?
> >
> > Foreign Server -> TLS-MailScanner -> TLS-Toaster
> >
> > How are others Using MailScanner in front of pop toasters 
> handling this
> > issue? It is looking as if moving the "User Check" to the 
> MailScanner
> > machine _is_ my one good option.
> >
> > Thanks,
> >
> > DAve
> >
> 
> Dave
> 
> not if you 550 reject on the inbound MTA. It never goes anywhere near
> MS, it simply drops the inbound connection with a "550 no 
> such address".
> 
> Any mistyped email address from a real user will get that message, ie
> they get a proper bounce message from their MTA.
> 
> Any spam attempts from automated/trojaned machines will just ignore it
> and carry on to the next victim.
Thanks Martin. Good, clear explanation.

Adressing your question about "How to protect pop toasters"... Well,
this is pretty much the same as protecting your M-Sexchange or Lotus
or ... any-mail ... setup. And dropping false adresses at the MTA level
on the ailScanner side is exactly what most do.

Have a fun time with the FAQ (this has been covered extensively on the
list to, so you might look through the archives), and setting things up.

Someone please correct me if I'm wrong, but you should be pretty
close...
If I understand you correctly, you already reject unknown addresses on
the toasters, so then you'd just need milter-ahead on the MS boxes.
... Or roll your own solution:-).

-- Glenn

> 
> --
> Martin Hepworth
> Snr Systems Administrator
> Solid State Logic
> Tel: +44 (0)1865 842300
> 
> 
> 
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