[CentOS] Recommend Mail Server
christopher.chan at bradbury.edu.hk
Tue Nov 24 06:47:28 UTC 2009
Les Mikesell wrote:
> Christopher Chan wrote:
>>> If you have a reasonably fast internal mailer you can just let mimedefang on
>>> your external relay check against it with smtp in real time. Exchange isn't one
>>> of those, though.
>> That internal mailer still has to whack something. You would just be
>> adding another layer again with the smtp latency. What is with the love
>> of uber number of layers?
> You are removing a layer if you just pass through the recipient check to the
> ultimate source (the internal delivery machine) before accepting, and it does in
> fact need to be able to handle the lookups at the speed real messages come in.
> However, your external relay is likely to get whacked with a dictionary attack
> that it needs to be able to reject quickly so you can't do that if the delivery
> box is slow.
OH are we? So what happens when the frontend hands off to the internal
delivery machine? Does not the internal delivery machine again do
> I used qmail for one of my domains a while back and it's practice of accepting
> everything, then sending bounces got a dictionary attack onto some kind of 'good
> to spam' list and I got about 50,000 messages/day for non-existing users for
> years afterwards. That was a problem until I put a sendmail with the good users
> in a virtuser table in front of it. Interestingly, the messages would come in
> from a large number of different IP addresses but in a sorted order and with
> clearly coordinated timing.
/me shudders to think of anyone running a pure qmail-1.03 for a mx.
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