greylisting question

[J.D. Bronson]

I have noticed (at times) that sometimes email gets greylisted
when the user doesn't exist in my system. The mail ultimately get's
rejected, but I cant figure out why it's greylisting when it's invalid 
to begin with? Greylisting, to me..should be the last resort..


I have this way up near the top of main.cf:

# REJECTING MAIL FOR UNKNOWN LOCAL USERS
local_recipient_maps = proxy:unix:passwd.byname $alias_maps

# ADDRESS REWRITING
alias_maps = $default_database_type:/etc/postfix/aliases
alias_database = $default_database_type:/etc/postfix/aliases


and then the typical stuff:

smtpd_recipient_restrictions =
        permit_mynetworks,
        reject_non_fqdn_sender,
        reject_non_fqdn_recipient,
        reject_unknown_sender_domain,
        reject_unknown_recipient_domain,
        reject_unauth_destination,
        reject_invalid_hostname,
        reject_non_fqdn_hostname,
        reject_unknown_client,
        reject_unauth_pipelining,
        check_policy_service    inet:127.0.0.1:10023






--
J.D. Bronson
Information Technology
Aurora Health Care - Milwaukee WI
Office: 414.978.8282 // Fax: 414.978.3988