sendmail message splitting defeats bandwidth savings?

Raymond Dijkxhoorn raymond at PROLOCATION.NET
Mon Nov 3 16:17:38 GMT 2003


> > Step 4 is unclear to me, if people have custom rules, and the one user
> > doenst want spam tagging and one user does, how will that be
> > combined into one message? In my eyes, you cant.

> Agreed, but there is a huge difference between splitting only those messages
> that need special handling (my suggested approach) and splitting ALL
> messages (the current approach).  In fact the difference for a site handling
> a significant amount of email is likely to be *many* orders of magnitude.

Very true. The other positive thing if MS can copy them is that it will
be generic, eg also Exim users can use it. Currently its limitted to
sendmail only as far a i know.

> Yes, but again, the question is *how much* it ought to increase.  The
> current approach has the potential to increase it drastically, with most of
> the increase being completely unrelated to productive mail filtering.
> Here's a more detailed example.  Suppose I want to whitelist mail to
> bob at but not to tom at or harry at  A single message comes
> in bound for all of them:
> To: bob at, tom at, harry at
> With queue group message splitting, it becomes three messages:
> To: bob at
> To: tom at
> To: harry at
> With MailScanner doing the message splitting on its own, there would only be
> a need to for two messages:
> To: bob at
> To: tom at, harry at
> Now suppose a message comes in for harry at and tom at  Even
> though there's no need for message splitting at all, sendmail queue groups
> would split the message in two, doubling its traffic.

Sure, but its all depending on your rulesets, and not generic :)

> I believe in most environments, the percentage of messages that actually
> need special whitelisting will be FAR outweighed by the percentage of
> messages that would just pass through MS untouched.
> And in my case, unfortunately, email messages may be 150MB in size,
> frequently sent to several local addresses.  Put those addresses behind a
> 192k/s link and multiplying the message-related bandwidth use becomes a big
> problem.

If you have 192k and a 150M limit then you should change your policy :))


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