duplicate suppression, sieve, loops, redirect and lost email

[Ragnar Sundblad]

Hello all,

Excuse me if I could have found the answers to those questions
on my own. I actually _have_ searched the list archives and the
web, but only got more questions. This subject seems to have
been partly discussed before.

We are using duplicate suppression and sieve.

When people do a sieve
 redirect "<myself>@<mydomain>" (that is, to themselves)
the email gets sent into the smtp world again, received again
and duplicate suppressions just silently discards the email
as has been discussed before.

This is obviously now what people want, and it is also
obviously very bad to loose email.

I have read that a sieve script could possible cause an
infinite mail loop if used without duplicate suppression,
and therefor you need to turn on duplicate suppression if
you are using sieve. When would that happen?

What I would rather assume would happen is that the email
would loop until sendmail (or whatever mta you are using)
returns it due to exceeded hop count. Is this not so?

We are using another machine as a front end mail distrubutor,
maybe that makes things different for us, but my simple
experiments and my maybe bad analysis indicates not.

/ragge