I have a postfix incoming mail scanning system for some domains... Like I
can't get a list of valid addreses I have used
reject_unverified_recipient... and have been reading a little about it's
parameters and wanted to ask you if I'm correct...
reject_unverified_recipient has the posibility of caching in wich if the
check with the destination server is ok (accepts mail for that recipient)
the result is cached 7 days (address_verify_positive_refresh_time) and
expires of the cache if after refreshes we can't have a refresh of this
recipient (for any reason) in 31 days
(address_verify_positive_expire_time). In this 31 days the status of the
recipient to non-valid can only change if remote destination servers sais
it doesn't exist any more (doesn't accept more mail for the recipient)...
Now for negative caching : when a remote destination server sais a
recipient doesn't exist it's cached 3 hours
(address_verify_negative_refresh_time) and if we can't obtain any status
for this recipient (either rejected or accepted) in 3 days
(address_verify_negative_expire_time) it's removed from the cache...
Each attempt in wich we don't obtain a valid result such us yes recipient
exists or not we ask verify thrice (address_verify_poll_count) to see if
he can obtain the information and between one attempt and the other there
are three seconds in wich we wait (address_verify_poll_delay)...