text_combined: thomas ledbetter htjdyuacrevelstonenet hi im wondering advice anyone regarding issue one users sends email large amount local users listed bcc contains sizable attachment sometimes trigger bcc storm single f5 load balancer various services flow single email transaction loop one piece equipment multiple times one bcc storms takes place looping max interfaces f5 weve taken measures prevent reducing number different types services pass load balancer reverted using rr dns instead im wondering else done taking look qshape postfix readme see discussion regarding default_destination_concurrency_limit parameter sounds promising affects destinations way control concurrency limits perhost basis tue 05 aug 2008 184919 0500 bcc mail storms