Re: [exim] Heads up?

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Autor: Steve Lamb
Data:  
Para: exim-users
Assunto: Re: [exim] Heads up?
John Palmer wrote:
> No, my MTA is *ATTEMPTING* to send 500 challenges a day, 90-95% of which
> NEVER leave my
> system because the return address on the spam is bogus! It never goes
> anywhere - GOT THAT?


    Yup.  Which of course ultimately shows how poorly this system scales.  You
get 500 a day.  Ok, now multiple that by 500 people, a tiny amount for a
corporate or educational email server, and how many CRs is the MTA trying to
process?  250,000.  Depending on the response they get the MTAs could be
trying multiple times per message so the actual delivery attempts are far
higher.  That's quite a bit if crap to be throwing out and keeping on your HD
for hours or even days.


    Now try to scale it to 5000 users.  50000 users.  It just doesn't scale.
It is not the magical bullet and when you do scale that high it becomes clear
that the clogging effect it has is detrimental.  Say you have 250,000
attempted CRs in a day for your small site of 500 users.  Say 50% of that are
spoofed AOL addresses.  You've just had AOLs servers do lookups, reject and
log 125,000 bad attempts.


    Dunno about you but if someone were bombing me with 125,000 attempted
messages to bogus addresses I'd be pretty pissed.  In fact, I get pissed any
time a dictonary attack hits my server from Brazil with a measely 200 addresses.


    So, please, tell me again how this is good for the 'net as a whole and how
you justify offloading your spam problems on other people in such a manner?


--
         Steve C. Lamb         | I'm your priest, I'm your shrink, I'm your
       PGP Key: 8B6E99C5       | main connection to the switchboard of souls.
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