Greylisting all your mail

If you turn on greylisting for all mail you will almost certainly want to make exceptions for mailing lists that use one-time sender addresses, because such mailing lists can pollute your greylist database relatively quickly.

 1 /etc/postfix/
main.cf:
 2     
smtpd_recipient_restrictions =
 3         
reject_unlisted_recipient
 4         ...
 5         
reject_unauth_destination 
 6         
check_sender_access hash:/etc/postfix/sender_access
 7         
check_policy_service unix:private/policy
 8         ...
 9 
10 /etc/postfix/sender_access:
11     securityfocus.com OK
12     ...

NOTES:

• Line 7: On Solaris you must use inet: style sockets instead of unix: style, as detailed in the " Example: greylist policy server" section above.

• Lines 6-7: Be sure to specify check_sender_access and check_policy_service AFTER reject_unauth_destination or else your system could become an open mail relay.

• Line 3: The greylist database gets polluted quickly with bogus addresses. It helps if you precede greylist lookups with restrictions that reject unknown senders and/or recipients.