David Saez Padros wrote:

>>> we use callbacks on a similar way, we do not do the callback
>>> if the incoming mail passes spf, dkim is not used to prevent
>>> callbacks because we do callbacks at RCPT time and dkim needs
>>> to reach DATA, we also use whitelisting to prevent callouts too
>> Can I ask why you don't do the call backs in DATA then? If I were to use 
>> callbacks, personally I'd want to make sure they were run at the very 
>> end of my spam filtering to reduce the likelyhood of my server being 
>> listed on an RBL for backscatter...
> 
> it takes less resouces to do the callback at rcpt than at the very
> end of the spam filtering

You could argue that using N lumps of somebody elses resources is worse 
than using 10xN lumps of your own. Especially if the 10xN is going idle, 
which on many systems it is...

> You can reduce the chance to get listed on a RBL by
> using spf, whitelists, etc .. (calloouts also have it's own cache)

True, that is an additional way to reduce the chance further.

> we have been using callouts since they exist without ever being
> blacklisted

You don't want to advertise that fact on mailing lists like this, or 
your listing status might get changed.

-- 
Mike Cardwell
(https://secure.grepular.com/) (http://perlcv.com/)

-- 
## List details at http://lists.exim.org/mailman/listinfo/exim-users 
## Exim details at http://www.exim.org/
## Please use the Wiki with this list - http://wiki.exim.org/

Reply via email to