Viktor Dukhovni:
> On Tue, Apr 22, 2014 at 01:50:49PM -0400, Wietse Venema wrote:
>
> > A global limit on the number of pending probes affects only unknown
> > email addresses. Postfix proactively refreshes known email addresses
> > well before they expire. I am not an idiot.
>
> Whether this is sufficient depends on the cache hit rate, and
> proportion of addresses that receive infrequent mail. Postfix does
> not send refresh probes unless the recipient is actually sent a
> message, right? The OP may benefit from a longer positive cache
> lifetime, and a separate transport for probes.
With the default expiration policy, inactive addresses (>31 days)
are the same as unknown recipients. Unless we're dealing with a
sustained flood of non-existent addresses, few real addresses should
be affected.
> Customers that tarpit probes are not doing anyone a favour, perhaps
> cluestick can be applied.
Yes, but they should not affect other customers too much. We're not
striving for total performance isolation.
Wietse
