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POSTGREY(1)	      User Contributed Perl Documentation	   POSTGREY(1)

NAME
       postgrey	- Postfix Greylisting Policy Server

SYNOPSIS
       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
	    --socketmode=MODE	unix socket permission (default	0666)
	-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/db/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 N bits from IP addresses, determined by ipv4cidr	and ipv6cidr (default)
	    --ipv4cidr=N	What cidr to use for the subnet	on IPv4	addresses when using lookup-by-subnet (default:	24)
	    --ipv6cidr=N	What cidr to use for the subnet	on IPv6	addresses when using lookup-by-subnet (default:	64)
	    --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: /usr/local/etc/postfix/postgrey_whitelist_clients
	    --whitelist-recipients=FILE	 default: /usr/local/etc/postfix/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
	    --x-greylist-header=TXT	 header	when a mail was	delayed	by greylisting
					 default: X-Greylist: delayed <seconds>	seconds	by postgrey-<version> at <server>; <date>

	Note that the --whitelist-x options can	be specified multiple times,
	and that per default /usr/local/etc/postfix/postgrey_whitelist_clients.local is
	also read, so that you can put there local entries.

DESCRIPTION
       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.

   Installation
       o   Create a "postgrey" user and	the directory where to put the
	   database dbdir (default: "/var/db/postgrey")

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

	    postgrey --inet=10023 -d

	   contrib/postgrey.init in the	postgrey source	distribution includes
	   a LSB-compliant init	script by Adrian von Bidder for	the Debian
	   system.

       o   Put something like this in /usr/local/etc/postfix/main.cf:

	    smtpd_recipient_restrictions =
			  permit_mynetworks
			  ...
			  reject_unauth_destination
			  check_policy_service inet:127.0.0.1:10023

       o   Install the provided	postgrey_whitelist_clients and
	   postgrey_whitelist_recipients in /usr/local/etc/postfix.

       o   Put in /usr/local/etc/postfix/postgrey_whitelist_recipients users
	   that	do not want greylisting.

   Whitelists
       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:

	/usr/local/etc/postfix/postgrey_whitelist_clients
	/usr/local/etc/postfix/postgrey_whitelist_clients.local
	/usr/local/etc/postfix/postgrey_whitelist_recipients

       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.addr" domain and subdomains.

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

       name@domain.addr
		 "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.addr" domain and subdomains.

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

       IP1.IP2.IP3.IP4/MASK
		 CIDR-syle network. Example: 192.168.1.0/24

       /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:

       o   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.

       o   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
       allowed.

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

	Greylisted, see	http://postgrey.schweikert.ch/help/example.com.html

       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	(example.com), so that domain-specific help can	be
       presented to the	user (on the default page it is	said to	contact
       postmaster@example.com)

       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	(example.com).

   Greylist Header
       When a message is greylisted, an	additional header can be prepended to
       the header section of the mail:

	X-Greylist: delayed %t seconds by postgrey-%v at %h; %d

       You can change the text with the	--x-greylist-header parameter. The
       following special variables will	be replaced in the text:

       %t  How many seconds the	mail has been delayed due to greylisting.

       %v  The version of postgrey.

       %d  The date.

       %h  The host.

   Privacy
       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 ALSO
       See <http://www.greylisting.org/> for a description of what greylisting
       is and <http://www.postfix.org/SMTPD_POLICY_README.html>	for a
       description of how Postfix policy servers work.

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

LICENSE
       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
       MERCHANTABILITY or FITNESS FOR A	PARTICULAR PURPOSE.  See the GNU
       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.

AUTHOR
       David Schweikert	<david@schweikert.ch>

perl v5.32.0			  2020-08-17			   POSTGREY(1)

NAME | SYNOPSIS | DESCRIPTION | COPYRIGHT | LICENSE | AUTHOR

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