Thanks Viktor,
>> 1) Once a client (or another MTA) establish a TCP connection with
>> listening port bounded by the SMTP daemon of Postfix, could happen that
>> more then one email messages are sent over that TCP connection, before
>> it
>> is closed?
>
> Sure this is possible, but it is unlikel to significantly impact your
> queues.
>
>> 2) If 1), is there any limit on the number of messages that could be
>> sent
>> over that TCP connection?
>
> No.
>
>> 3) Could the receiving MTA (i.e.: Postfix) decide how much times a TCP
>> connection could used to transmit a messages by a client?
>
> Enforcing such limits is unwise. The solution causes more harm than the
> perceived problem.
>
> There is no evidence that sender-side connection re-use has any material
> impact on your queues. If you do want to enforce such limits, they should
> be applied selectively to just IP sources with poor "reputations".
>
Indeed, it would be nice to have a tool that assigns a poor reputation to
an IP source that impact on the queues.. Maybe one of these tool could be
a Policyd server? Simply imposing a quota on the number of messages that
could be sent in a unit of time? Or there exists some of more refined, for
what you know?
rocsca
