Rich Pieri <rich.pieri@prescienttech.com> wrote:
>
>Richard Welty writes:
>
>> i have several hundred AOL subscribers on one of my lists. AOL MX hosts
>> are notorious for being overloaded and hard to deliver to. if i use an
>> intelligently conceived MTA, then when i do manage to get a connection to
>> AOL, i stand a good chance of getting the bulk of my AOL queue cleared
>> out in one session.
>
>This is where sendmail (+bulk_mailer) and exim connection caching is a
>really big win. Once you have a connection, these MTAs will keep that one
>connection open for several minutes.
This is where connection caching is a really big win for the sender,
who gets to stuff his full backlog at an overloaded receiver. How rude
and opportunistic. I consider this a denial-of-service attack.
Unloading your whole backlog through a single connection is hardly
being "conservative in what you send". Imagine what happens after AOL
is down for a while. When it comes back up, each remote sendmail hogs
a connection and dumps its load at the now *very* overloaded AOL. Not
nice.
qmail, on the other hand, independently retries each message, and
sends only one message per connection, which is *much* kinder to an
overloaded system.
>So, knowing that, I believe you have the perfect example of why qmail can
>be a bad choice of MTA.
*Any* MTA can be a bad choice. You have to match your resources and
requirements with the available set of MTA's. Anyone who says "FooMail
is the best MTA in all situations" is an idiot, for all values of
FooMail. This is *very* elementary system analysis.
-Dave
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