Here's something I'm testing out - greylisting based on server load levels:
defer log_message = DEFER - Host $sender_host_address - reverse lookup
failed! Load: $load_average
!verify = reverse_host_lookup
condition = ${if >{$load_average}{25000}{true}{false}}
$load_average = 1000 x real load so - 25000 = load of 25
The idea here being that under high load I put off senders that are
mostly spammers till the load level drops.
--
Marc Perkel - marc@???
Spam Filter: http://www.junkemailfilter.com
My Blog: http://marc.perkel.com