On 23.4.2014 21:22, Wietse Venema wrote:
1) Enforce a global limit on the number of outstanding verification
requests that equals, say, 1/4 of the capacity of the active queue.
3) The verify daemon keeps a cache with counters for the 1000 or
so most common domain names in a pending address verification
request.
Is the global limit going to be enforced by the queue manager?
If not, and given that neither of the counters above is persistent,
restarting postfix ~5 times under such attack once the domain limit is
reached will allow the queue to be clogged anyway... With every restart
allowing another batch of ( 80% * 1/4 * active_queue_size ) probes into
the active queue.
It won't be clogged indefinitely, sure, I am just pointing out that
tweaking the postfix config while under such attack might be problematic.
Patrik
