Весь пакет написан на perl /usr/sbin/postgrey - основной исполняемый файл.
Можно поменять и время через которое будет разрешено получение (delay) и сообщение отлупа (greylist_text)
Остальные параметры хорошо описаны в самом файле
Основные
postgrey - Postfix Greylisting Policy Server
=head1 SYNOPSIS
B<postgrey> [I<options>...]
-h, --help display this help and exit
--version output version information and exit
-v, --verbose increase verbosity level
-u, --unix=PATH listen on unix socket PATH
-i, --inet=[HOST:]PORT listen on PORT, localhost if HOST is not specified
-d, --daemonize run in the background
--pidfile=PATH put daemon pid into this file
--user=USER run as USER (default: postgrey)
--group=GROUP run as group GROUP (default: postgrey)
--dbdir=PATH put db files in PATH (default: /var/lib/postgrey)
--delay=N greylist for N seconds (default: 300)
--max-age=N delete entries older than N days since the last time
that they have been seen (default: 35)
--retry-window=N allow only N days for the first retrial (default: 2)
append 'h' if you want to specify it in hours
--greylist-action=A if greylisted, return A to Postfix (default: DEFER_IF_PERMIT)
--greylist-text=TXT response when a mail is greylisted
(default: Greylisted + help url, see below)
--lookup-by-subnet strip the last 8 bits from IP addresses (default)
--lookup-by-host do not strip the last 8 bits from IP addresses
--whitelist-clients=FILE default: /etc/postgrey/whitelist_clients
--whitelist-recipients=FILE default: /etc/postgrey/whitelist_recipients
--auto-whitelist-clients=N whitelist host after first successful delievery
N is the minimal count of mails before a client is
whitelisted (turned on by default with value 5)
specify N=0 to disable.
--privacy store data using one-way hash functions
--hostname=NAME set the hostname (default: `hostname`)
--exim don't reuse a socket for more than one query (exim compatible)
Note that the --whitelist-x options can be specified multiple times,
and that per default /etc/postgrey/whitelist_clients.local and
/etc/postgrey/whitelist_recipients.local are also read, so that you can put
there local entries.
Далее есть еще несколько интересных параметров, может кому пригодится