LDAP/MTA helping Spammers?

[Martin Hepworth]

Chris Lyon wrote:
> On Tue, 11 Jan 2005 10:46:10 +0100, Steen, Glenn <Glenn.Steen at ap1.se> wrote:
>
>>I'd tend to agree with Martin here. Even if the domain would be mapped,
>>ATM this type of thing has more benefit than badness.
>
>
> I am not disagreeing that the benefit isn't there but from a security
> standpoint it is always better to give less information that more
> information. So either at the MTA or in MS wouldn't it be better to
> just silently delete? Not sending any "User unknown"?
>

Depends on risk you attach to having your email addresses 'known'.

Also depends on the server load (66% of my inbound email is spam/malware
for non existant addresses)....and if the message does get through you
end up bouncing it by the final MX and then having to deal with the
bounce of the bounce as the 'from' address prob won't work either....

A straight '550 no such user' from the MailScanner inbound MTA is much
cleaner IHMO.

For me the risk of having someone brute force the email addresses buy
guessing is less than the email gateway being DOS-ed by thousands of
emails I need to get MS to process to decide what to do with it.

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


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