Emmanuel BILLOT:
> BUT
> when mails are blocked, there are stored in deferred queue. And when
> Postfix "replay" these deferred mails, slow down does'nt apply.
THIS IS ABSOLUTELY INCORRECT. The Postfix delivery rate does not
depend on whether a message comes from the deferred queue (new mail)
or from the deferred queue.
However, if a site has multiple MXes, and one MX rejects mail with
4XX, then Postfix will immediately try an alternate MX.
You can limit the number of MX sessions to just one with:
slow unix - - y - - smtp
-o smtp_mx_session_limit=1
-o smtp_mx_address_limit=5
With this Postfix will give up after the first session, but it will
still try five addresses if some address does not respond at all.
Wietse
> That is :
> - when all goes well, mails are sent and accepted
> - when somethinfg is "wrong" (flooding from a user), IP is blocked
> - we change IP, and all goes well again, but as Postix replay the deferred
> queue, everything is again considered as spam and IP is BL, and again, and
> again...
>
> Why does slow down not apply to deferred replay ?
> Is it possible to prevent Postfix to "flush" all when it replays mail ?
>
> Regards,
