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       postgrey - Postfix Greylisting Policy Server


       postgrey [options...]

        -h, --help              display this help and exit
            --version           output version information and exit
        -v, --verbose           increase verbosity level
            --syslog-facility   Syslog facility to use (default mail)
        -q, --quiet             decrease 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
            --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)
            --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 delivery
                                         N is the minimal count of mails before a client is
                                         whitelisted (turned on by default with value 5)
                                         specify N=0 to disable.
            --listen-queue-size=N        allow for N waiting connections to our socket

        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.


       Postgrey is a Postfix policy server implementing greylisting.

       When a request for delivery of a mail is received by Postfix via SMTP,
       the triplet "CLIENT_IP" / "SENDER" / "RECIPIENT" is built. If it is the
       first time that this triplet is seen, or if the triplet was first seen
       less than delay seconds (300 is the default), then the mail gets
       rejected with a temporary error. Hopefully spammers or viruses will not
       try again later, as it is however required per RFC.

       Note that you shouldn’t use the --lookup-by-host option unless you know
       what you are doing: there are a lot of mail servers that use a pool of
       addresses to send emails, so that they can change IP every time they
       try again. That’s why without this option postgrey will strip the last
       byte of the IP address when doing lookups in the database.

       ·   Create a "postgrey" user and the directory where to put the
           database dbdir (default: "/var/lib/postgrey")

       ·   Write an init script to start postgrey at boot and start it. Like
           this for example:

            postgrey --inet=10023 -d

       ·   Put something like this in /etc/

            smtpd_recipient_restrictions =
                          check_policy_service inet:

       ·   Install the provided whitelist_clients and whitelist_recipients in

       ·   Put in /etc/postgrey/whitelist_recipients users that do not want

       Whitelists allow you to specify client addresses or recipient address,
       for which no greylisting should be done. Per default postgrey will read
       the following files:


       You can specify alternative paths with the --whitelist-x options.

       Postgrey whitelists follow similar syntax rules as Postfix access
       tables.  The following can be specified for recipient addresses:

                 "domain.addr" domain and subdomains.

       name@     "name@.*" and extended addresses "name+blabla@.*".

                 "name@domain.addr" and extended addresses.

       /regexp/  anything that matches "regexp" (the full address is matched).

       The following can be specified for client addresses:

                 "domain.addr" domain and subdomains.

                 IP address IP1.IP2.IP3.IP4. You can also leave off one
                 number, in which case only the first specified numbers will
                 be checked.

                 CIDR-syle network. Example:

       /regexp/  anything that matches "regexp" (the full address is matched).

   Auto-whitelisting clients
       With the option --auto-whitelist-clients a client IP address will be
       automatically whitelisted if the following conditions are met:

       ·   At least 5 successfull attempts of delivering a mail (after
           greylisting was done). That number can be changed by specifying a
           number after the --auto-whitelist-clients argument. Only one
           attempt per hour counts.

       ·   The client was last seen before --max-age days (35 per default).

   Greylist Action
       To set the action to be returned to postfix when a message fails
       postgrey’s tests and should be deferred, use the
       --greylist-action=ACTION option.

       By default, postgrey returns DEFER_IF_PERMIT, which causes postfix to
       check the rest of the restrictions and defer the message only if it
       would otherwise be accepted.  A delay action of 451 causes postfix to
       always defer the message with an SMTP reply code of 451 (temp fail).

       See the postfix manual page access(5) for a discussion of the actions

   Greylist Text
       When a message is greylisted, an error message like this will be sent
       at the SMTP-level:

        Greylisted, see

       Usually no user should see that error message and the idea of that URL
       is to provide some help to system administrators seeing that message or
       users of broken mail clients which try to send mails directly and get a
       greylisting error. Note that the default help-URL contains the original
       recipient domain (, so that domain-specific help can be
       presented to the user (on the default page it is said to contact

       You can change the text (and URL) with the --greylist-text parameter.
       The following special variables will be replaced in the text:

       %s  How many seconds left until the greylisting is over (300).

       %r  Mail-domain of the recipient (

       The --privacy option enable the use of a SHA1 hash function to store
       IPs and emails in the greylisting database.  This will defeat straight
       forward attempts to retrieve mail user behaviours.

       See <> for a description of what greylisting
       is and <> for a
       description of how Postfix policy servers work.


       Copyright (c) 2004-2007 by ETH Zurich. All rights reserved.  Copyright
       (c) 2007 by Open Systems AG. All rights reserved.


       This program is free software; you can redistribute it and/or modify it
       under the terms of the GNU General Public License as published by the
       Free Software Foundation; either version 2 of the License, or (at your
       option) any later version.

       This program is distributed in the hope that it will be useful, but
       WITHOUT ANY WARRANTY; without even the implied warranty of
       General Public License for more details.

       You should have received a copy of the GNU General Public License along
       with this program; if not, write to the Free Software Foundation, Inc.,
       675 Mass Ave, Cambridge, MA 02139, USA.


       David Schweikert <>