hosts/flora-6/mailman.nix

@@ -4,7 +4,12 @@
   pkgs,
   self,
   ...
-}: {
+}: let
+  postfixConfig = pkgs.writeTextFile {
+    name = "main.cf";
+    text = builtins.readFile ./postfix/main.cf;
+  };
+in {
   system.activationScripts.mkMailmanNet = let
     docker = config.virtualisation.oci-containers.backend;
     dockerBin = "${pkgs.${docker}}/bin/${docker}";
@@ -60,6 +65,7 @@
         environment = {
           DATABASE_TYPE = "postgres";
           DATABASE_CLASS = "mailman.database.postgresql.PostgreSQLDatabase";
+          MTA = "postfix";
         };
         environmentFiles = [
           config.age.secrets.mailman-core-secrets.path
@@ -109,6 +115,25 @@
           config.age.secrets.mailman-db-secrets.path
         ];
       };
+
+      containers."mailman-postfix" = {
+        image = "mailu/postfix:1.9.46";
+        autoStart = true;
+        user = "993";
+        extraOptions = [
+          "--network=mailman-net"
+        ];
+        volumes = [
+          "/var/lib/mailman/postfix/overrides:/overrides:ro"
+          "/var/lib/mailman/postfix/mailqueue:/var/spool/postfix"
+          "/var/lib/mailman/postfix/data:/var/lib/postfix"
+          "/var/lib/mailman/core:/var/lib/mailman/core"
+          "${postfixConfig}/bin/main.cf:/etc/postfix/main.cf"
+        ];
+        environmentFiles = [
+          config.age.secrets.mailman-db-secrets.path
+        ];
+      };
     };
   };
 }

hosts/flora-6/postfix/main.cf

@@ -0,0 +1,692 @@
+# Global Postfix configuration file. This file lists only a subset
+# of all parameters. For the syntax, and for a complete parameter
+# list, see the postconf(5) manual page (command: "man 5 postconf").
+#
+# For common configuration examples, see BASIC_CONFIGURATION_README
+# and STANDARD_CONFIGURATION_README. To find these documents, use
+# the command "postconf html_directory readme_directory", or go to
+# http://www.postfix.org/BASIC_CONFIGURATION_README.html etc.
+#
+# For best results, change no more than 2-3 parameters at a time,
+# and test if Postfix still works after every change.
+
+# COMPATIBILITY
+#
+# The compatibility_level determines what default settings Postfix
+# will use for main.cf and master.cf settings. These defaults will
+# change over time.
+#
+# To avoid breaking things, Postfix will use backwards-compatible
+# default settings and log where it uses those old backwards-compatible
+# default settings, until the system administrator has determined
+# if any backwards-compatible default settings need to be made
+# permanent in main.cf or master.cf.
+#
+# When this review is complete, update the compatibility_level setting
+# below as recommended in the RELEASE_NOTES file.
+#
+# The level below is what should be used with new (not upgrade) installs.
+#
+compatibility_level = 3.6
+
+# SOFT BOUNCE
+#
+# The soft_bounce parameter provides a limited safety net for
+# testing.  When soft_bounce is enabled, mail will remain queued that
+# would otherwise bounce. This parameter disables locally-generated
+# bounces, and prevents the SMTP server from rejecting mail permanently
+# (by changing 5xx replies into 4xx replies). However, soft_bounce
+# is no cure for address rewriting mistakes or mail routing mistakes.
+#
+#soft_bounce = no
+
+# LOCAL PATHNAME INFORMATION
+#
+# The queue_directory specifies the location of the Postfix queue.
+# This is also the root directory of Postfix daemons that run chrooted.
+# See the files in examples/chroot-setup for setting up Postfix chroot
+# environments on different UNIX systems.
+#
+queue_directory = /var/spool/postfix
+
+# The command_directory parameter specifies the location of all
+# postXXX commands.
+#
+command_directory = /usr/sbin
+
+# The daemon_directory parameter specifies the location of all Postfix
+# daemon programs (i.e. programs listed in the master.cf file). This
+# directory must be owned by root.
+#
+daemon_directory = /usr/libexec/postfix
+
+# The data_directory parameter specifies the location of Postfix-writable
+# data files (caches, random numbers). This directory must be owned
+# by the mail_owner account (see below).
+#
+data_directory = /var/lib/postfix
+
+# QUEUE AND PROCESS OWNERSHIP
+#
+# The mail_owner parameter specifies the owner of the Postfix queue
+# and of most Postfix daemon processes.  Specify the name of a user
+# account THAT DOES NOT SHARE ITS USER OR GROUP ID WITH OTHER ACCOUNTS
+# AND THAT OWNS NO OTHER FILES OR PROCESSES ON THE SYSTEM.  In
+# particular, don't specify nobody or daemon. PLEASE USE A DEDICATED
+# USER.
+#
+mail_owner = postfix
+
+# The default_privs parameter specifies the default rights used by
+# the local delivery agent for delivery to external file or command.
+# These rights are used in the absence of a recipient user context.
+# DO NOT SPECIFY A PRIVILEGED USER OR THE POSTFIX OWNER.
+#
+#default_privs = nobody
+
+# INTERNET HOST AND DOMAIN NAMES
+#
+# The myhostname parameter specifies the internet hostname of this
+# mail system. The default is to use the fully-qualified domain name
+# from gethostname(). $myhostname is used as a default value for many
+# other configuration parameters.
+#
+myhostname = list.pub.solar
+#myhostname = virtual.domain.tld
+
+# The mydomain parameter specifies the local internet domain name.
+# The default is to use $myhostname minus the first component.
+# $mydomain is used as a default value for many other configuration
+# parameters.
+#
+#mydomain = domain.tld
+
+# SENDING MAIL
+#
+# The myorigin parameter specifies the domain that locally-posted
+# mail appears to come from. The default is to append $myhostname,
+# which is fine for small sites.  If you run a domain with multiple
+# machines, you should (1) change this to $mydomain and (2) set up
+# a domain-wide alias database that aliases each user to
+# user@that.users.mailhost.
+#
+# For the sake of consistency between sender and recipient addresses,
+# myorigin also specifies the default domain name that is appended
+# to recipient addresses that have no @domain part.
+#
+#myorigin = $myhostname
+#myorigin = $mydomain
+
+# RECEIVING MAIL
+
+# The inet_interfaces parameter specifies the network interface
+# addresses that this mail system receives mail on.  By default,
+# the software claims all active interfaces on the machine. The
+# parameter also controls delivery of mail to user@[ip.address].
+#
+# See also the proxy_interfaces parameter, for network addresses that
+# are forwarded to us via a proxy or network address translator.
+#
+# Note: you need to stop/start Postfix when this parameter changes.
+#
+#inet_interfaces = all
+#inet_interfaces = $myhostname
+#inet_interfaces = $myhostname, localhost
+
+# The proxy_interfaces parameter specifies the network interface
+# addresses that this mail system receives mail on by way of a
+# proxy or network address translation unit. This setting extends
+# the address list specified with the inet_interfaces parameter.
+#
+# You must specify your proxy/NAT addresses when your system is a
+# backup MX host for other domains, otherwise mail delivery loops
+# will happen when the primary MX host is down.
+#
+#proxy_interfaces =
+#proxy_interfaces = 1.2.3.4
+
+# The mydestination parameter specifies the list of domains that this
+# machine considers itself the final destination for.
+#
+# These domains are routed to the delivery agent specified with the
+# local_transport parameter setting. By default, that is the UNIX
+# compatible delivery agent that lookups all recipients in /etc/passwd
+# and /etc/aliases or their equivalent.
+#
+# The default is $myhostname + localhost.$mydomain + localhost.  On
+# a mail domain gateway, you should also include $mydomain.
+#
+# Do not specify the names of virtual domains - those domains are
+# specified elsewhere (see VIRTUAL_README).
+#
+# Do not specify the names of domains that this machine is backup MX
+# host for. Specify those names via the relay_domains settings for
+# the SMTP server, or use permit_mx_backup if you are lazy (see
+# STANDARD_CONFIGURATION_README).
+#
+# The local machine is always the final destination for mail addressed
+# to user@[the.net.work.address] of an interface that the mail system
+# receives mail on (see the inet_interfaces parameter).
+#
+# Specify a list of host or domain names, /file/name or type:table
+# patterns, separated by commas and/or whitespace. A /file/name
+# pattern is replaced by its contents; a type:table is matched when
+# a name matches a lookup key (the right-hand side is ignored).
+# Continue long lines by starting the next line with whitespace.
+#
+# See also below, section "REJECTING MAIL FOR UNKNOWN LOCAL USERS".
+#
+#mydestination = $myhostname, localhost.$mydomain, localhost
+#mydestination = $myhostname, localhost.$mydomain, localhost, $mydomain
+#mydestination = $myhostname, localhost.$mydomain, localhost, $mydomain,
+#	mail.$mydomain, www.$mydomain, ftp.$mydomain
+
+# REJECTING MAIL FOR UNKNOWN LOCAL USERS
+#
+# The local_recipient_maps parameter specifies optional lookup tables
+# with all names or addresses of users that are local with respect
+# to $mydestination, $inet_interfaces or $proxy_interfaces.
+#
+# If this parameter is defined, then the SMTP server will reject
+# mail for unknown local users. This parameter is defined by default.
+#
+# To turn off local recipient checking in the SMTP server, specify
+# local_recipient_maps = (i.e. empty).
+#
+# The default setting assumes that you use the default Postfix local
+# delivery agent for local delivery. You need to update the
+# local_recipient_maps setting if:
+#
+# - You define $mydestination domain recipients in files other than
+#   /etc/passwd, /etc/aliases, or the $virtual_alias_maps files.
+#   For example, you define $mydestination domain recipients in
+#   the $virtual_mailbox_maps files.
+#
+# - You redefine the local delivery agent in master.cf.
+#
+# - You redefine the "local_transport" setting in main.cf.
+#
+# - You use the "luser_relay", "mailbox_transport", or "fallback_transport"
+#   feature of the Postfix local delivery agent (see local(8)).
+#
+# Details are described in the LOCAL_RECIPIENT_README file.
+#
+# Beware: if the Postfix SMTP server runs chrooted, you probably have
+# to access the passwd file via the proxymap service, in order to
+# overcome chroot restrictions. The alternative, having a copy of
+# the system passwd file in the chroot jail is just not practical.
+#
+# The right-hand side of the lookup tables is conveniently ignored.
+# In the left-hand side, specify a bare username, an @domain.tld
+# wild-card, or specify a user@domain.tld address.
+#
+#local_recipient_maps = unix:passwd.byname $alias_maps
+#local_recipient_maps = proxy:unix:passwd.byname $alias_maps
+#local_recipient_maps =
+
+# The unknown_local_recipient_reject_code specifies the SMTP server
+# response code when a recipient domain matches $mydestination or
+# ${proxy,inet}_interfaces, while $local_recipient_maps is non-empty
+# and the recipient address or address local-part is not found.
+#
+# The default setting is 550 (reject mail) but it is safer to start
+# with 450 (try again later) until you are certain that your
+# local_recipient_maps settings are OK.
+#
+# unknown_local_recipient_reject_code = 550
+
+# TRUST AND RELAY CONTROL
+
+# The mynetworks parameter specifies the list of "trusted" SMTP
+# clients that have more privileges than "strangers".
+#
+# In particular, "trusted" SMTP clients are allowed to relay mail
+# through Postfix.  See the smtpd_recipient_restrictions parameter
+# in postconf(5).
+#
+# You can specify the list of "trusted" network addresses by hand
+# or you can let Postfix do it for you (which is the default).
+#
+# By default (mynetworks_style = subnet), Postfix "trusts" SMTP
+# clients in the same IP subnetworks as the local machine.
+# On Linux, this works correctly only with interfaces specified
+# with the "ifconfig" command.
+#
+# Specify "mynetworks_style = class" when Postfix should "trust" SMTP
+# clients in the same IP class A/B/C networks as the local machine.
+# Don't do this with a dialup site - it would cause Postfix to "trust"
+# your entire provider's network.  Instead, specify an explicit
+# mynetworks list by hand, as described below.
+#
+# Specify "mynetworks_style = host" when Postfix should "trust"
+# only the local machine.
+#
+#mynetworks_style = class
+#mynetworks_style = subnet
+#mynetworks_style = host
+
+# Alternatively, you can specify the mynetworks list by hand, in
+# which case Postfix ignores the mynetworks_style setting.
+#
+# Specify an explicit list of network/netmask patterns, where the
+# mask specifies the number of bits in the network part of a host
+# address.
+#
+# You can also specify the absolute pathname of a pattern file instead
+# of listing the patterns here. Specify type:table for table-based lookups
+# (the value on the table right-hand side is not used).
+#
+mynetworks = mailman-core,mailman-web
+#mynetworks = $config_directory/mynetworks
+#mynetworks = hash:/etc/postfix/network_table
+
+# The relay_domains parameter restricts what destinations this system will
+# relay mail to.  See the smtpd_recipient_restrictions description in
+# postconf(5) for detailed information.
+#
+# By default, Postfix relays mail
+# - from "trusted" clients (IP address matches $mynetworks) to any destination,
+# - from "untrusted" clients to destinations that match $relay_domains or
+#   subdomains thereof, except addresses with sender-specified routing.
+# The default relay_domains value is $mydestination.
+#
+# In addition to the above, the Postfix SMTP server by default accepts mail
+# that Postfix is final destination for:
+# - destinations that match $inet_interfaces or $proxy_interfaces,
+# - destinations that match $mydestination
+# - destinations that match $virtual_alias_domains,
+# - destinations that match $virtual_mailbox_domains.
+# These destinations do not need to be listed in $relay_domains.
+#
+# Specify a list of hosts or domains, /file/name patterns or type:name
+# lookup tables, separated by commas and/or whitespace.  Continue
+# long lines by starting the next line with whitespace. A file name
+# is replaced by its contents; a type:name table is matched when a
+# (parent) domain appears as lookup key.
+#
+# NOTE: Postfix will not automatically forward mail for domains that
+# list this system as their primary or backup MX host. See the
+# permit_mx_backup restriction description in postconf(5).
+#
+#relay_domains = $mydestination
+
+# INTERNET OR INTRANET
+
+# The relayhost parameter specifies the default host to send mail to
+# when no entry is matched in the optional transport(5) table. When
+# no relayhost is given, mail is routed directly to the destination.
+#
+# On an intranet, specify the organizational domain name. If your
+# internal DNS uses no MX records, specify the name of the intranet
+# gateway host instead.
+#
+# In the case of SMTP, specify a domain, host, host:port, [host]:port,
+# [address] or [address]:port; the form [host] turns off MX lookups.
+#
+# If you're connected via UUCP, see also the default_transport parameter.
+#
+#relayhost = $mydomain
+#relayhost = [gateway.my.domain]
+#relayhost = [mailserver.isp.tld]
+#relayhost = uucphost
+#relayhost = [an.ip.add.ress]
+
+# REJECTING UNKNOWN RELAY USERS
+#
+# The relay_recipient_maps parameter specifies optional lookup tables
+# with all addresses in the domains that match $relay_domains.
+#
+# If this parameter is defined, then the SMTP server will reject
+# mail for unknown relay users. This feature is off by default.
+#
+# The right-hand side of the lookup tables is conveniently ignored.
+# In the left-hand side, specify an @domain.tld wild-card, or specify
+# a user@domain.tld address.
+#
+#relay_recipient_maps = hash:/etc/postfix/relay_recipients
+
+# INPUT RATE CONTROL
+#
+# The in_flow_delay configuration parameter implements mail input
+# flow control. This feature is turned on by default, although it
+# still needs further development (it's disabled on SCO UNIX due
+# to an SCO bug).
+#
+# A Postfix process will pause for $in_flow_delay seconds before
+# accepting a new message, when the message arrival rate exceeds the
+# message delivery rate. With the default 100 SMTP server process
+# limit, this limits the mail inflow to 100 messages a second more
+# than the number of messages delivered per second.
+#
+# Specify 0 to disable the feature. Valid delays are 0..10.
+#
+#in_flow_delay = 1s
+
+# ADDRESS REWRITING
+#
+# The ADDRESS_REWRITING_README document gives information about
+# address masquerading or other forms of address rewriting including
+# username->Firstname.Lastname mapping.
+
+# ADDRESS REDIRECTION (VIRTUAL DOMAIN)
+#
+# The VIRTUAL_README document gives information about the many forms
+# of domain hosting that Postfix supports.
+
+# "USER HAS MOVED" BOUNCE MESSAGES
+#
+# See the discussion in the ADDRESS_REWRITING_README document.
+
+# TRANSPORT MAP
+#
+# See the discussion in the ADDRESS_REWRITING_README document.
+
+# ALIAS DATABASE
+#
+# The alias_maps parameter specifies the list of alias databases used
+# by the local delivery agent. The default list is system dependent.
+#
+# On systems with NIS, the default is to search the local alias
+# database, then the NIS alias database. See aliases(5) for syntax
+# details.
+#
+# If you change the alias database, run "postalias /etc/aliases" (or
+# wherever your system stores the mail alias file), or simply run
+# "newaliases" to build the necessary DBM or DB file.
+#
+# It will take a minute or so before changes become visible.  Use
+# "postfix reload" to eliminate the delay.
+#
+#alias_maps = dbm:/etc/aliases
+#alias_maps = hash:/etc/aliases
+#alias_maps = hash:/etc/aliases, nis:mail.aliases
+#alias_maps = netinfo:/aliases
+
+# The alias_database parameter specifies the alias database(s) that
+# are built with "newaliases" or "sendmail -bi".  This is a separate
+# configuration parameter, because alias_maps (see above) may specify
+# tables that are not necessarily all under control by Postfix.
+#
+#alias_database = dbm:/etc/aliases
+#alias_database = dbm:/etc/mail/aliases
+#alias_database = hash:/etc/aliases
+#alias_database = hash:/etc/aliases, hash:/opt/majordomo/aliases
+
+# ADDRESS EXTENSIONS (e.g., user+foo)
+#
+# The recipient_delimiter parameter specifies the separator between
+# user names and address extensions (user+foo). See canonical(5),
+# local(8), relocated(5) and virtual(5) for the effects this has on
+# aliases, canonical, virtual, relocated and .forward file lookups.
+# Basically, the software tries user+foo and .forward+foo before
+# trying user and .forward.
+#
+#recipient_delimiter = +
+
+# DELIVERY TO MAILBOX
+#
+# The home_mailbox parameter specifies the optional pathname of a
+# mailbox file relative to a user's home directory. The default
+# mailbox file is /var/spool/mail/user or /var/mail/user.  Specify
+# "Maildir/" for qmail-style delivery (the / is required).
+#
+#home_mailbox = Mailbox
+#home_mailbox = Maildir/
+
+# The mail_spool_directory parameter specifies the directory where
+# UNIX-style mailboxes are kept. The default setting depends on the
+# system type.
+#
+#mail_spool_directory = /var/mail
+#mail_spool_directory = /var/spool/mail
+
+# The mailbox_command parameter specifies the optional external
+# command to use instead of mailbox delivery. The command is run as
+# the recipient with proper HOME, SHELL and LOGNAME environment settings.
+# Exception:  delivery for root is done as $default_user.
+#
+# Other environment variables of interest: USER (recipient username),
+# EXTENSION (address extension), DOMAIN (domain part of address),
+# and LOCAL (the address localpart).
+#
+# Unlike other Postfix configuration parameters, the mailbox_command
+# parameter is not subjected to $parameter substitutions. This is to
+# make it easier to specify shell syntax (see example below).
+#
+# Avoid shell meta characters because they will force Postfix to run
+# an expensive shell process. Procmail alone is expensive enough.
+#
+# IF YOU USE THIS TO DELIVER MAIL SYSTEM-WIDE, YOU MUST SET UP AN
+# ALIAS THAT FORWARDS MAIL FOR ROOT TO A REAL USER.
+#
+#mailbox_command = /some/where/procmail
+#mailbox_command = /some/where/procmail -a "$EXTENSION"
+
+# The mailbox_transport specifies the optional transport in master.cf
+# to use after processing aliases and .forward files. This parameter
+# has precedence over the mailbox_command, fallback_transport and
+# luser_relay parameters.
+#
+# Specify a string of the form transport:nexthop, where transport is
+# the name of a mail delivery transport defined in master.cf.  The
+# :nexthop part is optional. For more details see the sample transport
+# configuration file.
+#
+# NOTE: if you use this feature for accounts not in the UNIX password
+# file, then you must update the "local_recipient_maps" setting in
+# the main.cf file, otherwise the SMTP server will reject mail for
+# non-UNIX accounts with "User unknown in local recipient table".
+#
+# Cyrus IMAP over LMTP. Specify ``lmtpunix      cmd="lmtpd"
+# listen="/var/imap/socket/lmtp" prefork=0'' in cyrus.conf.
+#mailbox_transport = lmtp:unix:/var/imap/socket/lmtp
+#
+# Cyrus IMAP via command line. Uncomment the "cyrus...pipe" and
+# subsequent line in master.cf.
+#mailbox_transport = cyrus
+
+# The fallback_transport specifies the optional transport in master.cf
+# to use for recipients that are not found in the UNIX passwd database.
+# This parameter has precedence over the luser_relay parameter.
+#
+# Specify a string of the form transport:nexthop, where transport is
+# the name of a mail delivery transport defined in master.cf.  The
+# :nexthop part is optional. For more details see the sample transport
+# configuration file.
+#
+# NOTE: if you use this feature for accounts not in the UNIX password
+# file, then you must update the "local_recipient_maps" setting in
+# the main.cf file, otherwise the SMTP server will reject mail for
+# non-UNIX accounts with "User unknown in local recipient table".
+#
+#fallback_transport = lmtp:unix:/file/name
+#fallback_transport = cyrus
+#fallback_transport =
+
+# The luser_relay parameter specifies an optional destination address
+# for unknown recipients.  By default, mail for unknown@$mydestination,
+# unknown@[$inet_interfaces] or unknown@[$proxy_interfaces] is returned
+# as undeliverable.
+#
+# The following expansions are done on luser_relay: $user (recipient
+# username), $shell (recipient shell), $home (recipient home directory),
+# $recipient (full recipient address), $extension (recipient address
+# extension), $domain (recipient domain), $local (entire recipient
+# localpart), $recipient_delimiter. Specify ${name?value} or
+# ${name:value} to expand value only when $name does (does not) exist.
+#
+# luser_relay works only for the default Postfix local delivery agent.
+#
+# NOTE: if you use this feature for accounts not in the UNIX password
+# file, then you must specify "local_recipient_maps =" (i.e. empty) in
+# the main.cf file, otherwise the SMTP server will reject mail for
+# non-UNIX accounts with "User unknown in local recipient table".
+#
+#luser_relay = $user@other.host
+#luser_relay = $local@other.host
+#luser_relay = admin+$local
+
+# JUNK MAIL CONTROLS
+#
+# The controls listed here are only a very small subset. The file
+# SMTPD_ACCESS_README provides an overview.
+
+# The header_checks parameter specifies an optional table with patterns
+# that each logical message header is matched against, including
+# headers that span multiple physical lines.
+#
+# By default, these patterns also apply to MIME headers and to the
+# headers of attached messages. With older Postfix versions, MIME and
+# attached message headers were treated as body text.
+#
+# For details, see "man header_checks".
+#
+#header_checks = regexp:/etc/postfix/header_checks
+
+# FAST ETRN SERVICE
+#
+# Postfix maintains per-destination logfiles with information about
+# deferred mail, so that mail can be flushed quickly with the SMTP
+# "ETRN domain.tld" command, or by executing "sendmail -qRdomain.tld".
+# See the ETRN_README document for a detailed description.
+#
+# The fast_flush_domains parameter controls what destinations are
+# eligible for this service. By default, they are all domains that
+# this server is willing to relay mail to.
+#
+#fast_flush_domains = $relay_domains
+
+# SHOW SOFTWARE VERSION OR NOT
+#
+# The smtpd_banner parameter specifies the text that follows the 220
+# code in the SMTP server's greeting banner. Some people like to see
+# the mail version advertised. By default, Postfix shows no version.
+#
+# You MUST specify $myhostname at the start of the text. That is an
+# RFC requirement. Postfix itself does not care.
+#
+#smtpd_banner = $myhostname ESMTP $mail_name
+#smtpd_banner = $myhostname ESMTP $mail_name ($mail_version)
+
+# PARALLEL DELIVERY TO THE SAME DESTINATION
+#
+# How many parallel deliveries to the same user or domain? With local
+# delivery, it does not make sense to do massively parallel delivery
+# to the same user, because mailbox updates must happen sequentially,
+# and expensive pipelines in .forward files can cause disasters when
+# too many are run at the same time. With SMTP deliveries, 10
+# simultaneous connections to the same domain could be sufficient to
+# raise eyebrows.
+#
+# Each message delivery transport has its XXX_destination_concurrency_limit
+# parameter.  The default is $default_destination_concurrency_limit for
+# most delivery transports. For the local delivery agent the default is 2.
+
+#local_destination_concurrency_limit = 2
+#default_destination_concurrency_limit = 20
+
+# DEBUGGING CONTROL
+#
+# The debug_peer_level parameter specifies the increment in verbose
+# logging level when an SMTP client or server host name or address
+# matches a pattern in the debug_peer_list parameter.
+#
+debug_peer_level = 2
+
+# The debug_peer_list parameter specifies an optional list of domain
+# or network patterns, /file/name patterns or type:name tables. When
+# an SMTP client or server host name or address matches a pattern,
+# increase the verbose logging level by the amount specified in the
+# debug_peer_level parameter.
+#
+#debug_peer_list = 127.0.0.1
+#debug_peer_list = some.domain
+
+# The debugger_command specifies the external command that is executed
+# when a Postfix daemon program is run with the -D option.
+#
+# Use "command .. & sleep 5" so that the debugger can attach before
+# the process marches on. If you use an X-based debugger, be sure to
+# set up your XAUTHORITY environment variable before starting Postfix.
+#
+debugger_command =
+  PATH=/bin:/usr/bin:/usr/local/bin:/usr/X11R6/bin
+  ddd $daemon_directory/$process_name $process_id & sleep 5
+
+# If you can't use X, use this to capture the call stack when a
+# daemon crashes. The result is in a file in the configuration
+# directory, and is named after the process name and the process ID.
+#
+# debugger_command =
+#	PATH=/bin:/usr/bin:/usr/local/bin; export PATH; (echo cont;
+#	echo where) | gdb $daemon_directory/$process_name $process_id 2>&1
+#	>$config_directory/$process_name.$process_id.log & sleep 5
+#
+# Another possibility is to run gdb under a detached screen session.
+# To attach to the screen session, su root and run "screen -r
+# <id_string>" where <id_string> uniquely matches one of the detached
+# sessions (from "screen -list").
+#
+# debugger_command =
+#	PATH=/bin:/usr/bin:/sbin:/usr/sbin; export PATH; screen
+#	-dmS $process_name gdb $daemon_directory/$process_name
+#	$process_id & sleep 1
+
+# INSTALL-TIME CONFIGURATION INFORMATION
+#
+# The following parameters are used when installing a new Postfix version.
+#
+# sendmail_path: The full pathname of the Postfix sendmail command.
+# This is the Sendmail-compatible mail posting interface.
+#
+sendmail_path = /usr/sbin/sendmail
+
+# newaliases_path: The full pathname of the Postfix newaliases command.
+# This is the Sendmail-compatible command to build alias databases.
+#
+newaliases_path = /usr/bin/newaliases
+
+# mailq_path: The full pathname of the Postfix mailq command.  This
+# is the Sendmail-compatible mail queue listing command.
+#
+mailq_path = /usr/bin/mailq
+
+# setgid_group: The group for mail submission and queue management
+# commands.  This must be a group name with a numerical group ID that
+# is not shared with other accounts, not even with the Postfix account.
+#
+setgid_group = postdrop
+
+# html_directory: The location of the Postfix HTML documentation.
+#
+html_directory = no
+
+# manpage_directory: The location of the Postfix on-line manual pages.
+#
+manpage_directory = /usr/share/man
+
+# sample_directory: The location of the Postfix sample configuration files.
+# This parameter is obsolete as of Postfix 2.1.
+#
+sample_directory = /etc/postfix
+
+# readme_directory: The location of the Postfix README files.
+#
+readme_directory = /usr/share/doc/postfix/readme
+inet_protocols = ipv4
+meta_directory = /etc/postfix
+shlib_directory = /usr/lib/postfix
+
+
+# Config below taken and adapted from
+# https://github.com/maxking/docker-mailman#postfix
+recipient_delimiter = +
+unknown_local_recipient_reject_code = 550
+owner_request_special = no
+
+transport_maps =
+    regexp:/var/lib/mailman/core/var/data/postfix_lmtp
+local_recipient_maps =
+    regexp:/var/lib/mailman/core/var/data/postfix_lmtp
+relay_domains =
+    regexp:/var/lib/mailman/core/var/data/postfix_domains