プロバイダの迷惑メール対策で、自宅でメールサーバーを構築するのは難しくなりました。
それでも、メールサーバーはぜひとも構築したいサーバーではないでしょうか。
送信メールサーバーは Postfix、受信メールサーバーは Dovecot(ダブコット)の構成が標準になっております。(これ一択?)

root@meckk:~# aptitude -y install postfix postfix-tls sasl2-bin 
The following NEW packages will be installed:
  db4.8-util{a} postfix{b} python{a} python-minimal{a} python2.6{a} python2.6-minimal{a} sasl2-bin
0 packages upgraded, 7 newly installed, 0 to remove and 0 not upgraded.
Need to get 5658 kB of archives. After unpacking 19.2 MB will be used.
The following packages have unmet dependencies:
  exim4-config: Conflicts: postfix but 2.7.1-1+squeeze1 is to be installed.
  postfix: Conflicts: mail-transport-agent which is a virtual package.
  exim4-daemon-light: Conflicts: mail-transport-agent which is a virtual package.
The following actions will resolve these dependencies:

     Remove the following packages:
1)     exim4-base
2)     exim4-config
3)     exim4-daemon-light



The following NEW packages will be installed:
  db4.8-util{a} postfix python{a} python-minimal{a} python2.6{a} python2.6-minimal{a} sasl2-bin
The following packages will be REMOVED:
  exim4-base{a} exim4-config{a} exim4-daemon-light{a}
0 packages upgraded, 7 newly installed, 3 to remove and 0 not upgraded.
Need to get 5658 kB of archives. After unpacking 15.2 MB will be used.
Get:1 http://ftp.riken.jp/Linux/debian/debian/ squeeze/main python2.6-minimal armel 2.6.6-8+b1 [1416 kB]
Get:2 http://ftp.riken.jp/Linux/debian/debian/ squeeze/main python2.6 armel 2.6.6-8+b1 [2421 kB]
Get:3 http://ftp.riken.jp/Linux/debian/debian/ squeeze/main python-minimal all 2.6.6-3+squeeze7 [33.8 kB]
Get:4 http://ftp.riken.jp/Linux/debian/debian/ squeeze/main python all 2.6.6-3+squeeze7 [169 kB]
Get:5 http://ftp.riken.jp/Linux/debian/debian/ squeeze/main db4.8-util armel 4.8.30-2 [129 kB]
Get:6 http://ftp.riken.jp/Linux/debian/debian/ squeeze/main sasl2-bin armel 2.1.23.dfsg1-7 [150 kB]
Get:7 http://ftp.riken.jp/Linux/debian/debian/ squeeze/main postfix armel 2.7.1-1+squeeze1 [1339 kB]
Fetched 5658 kB in 1min 1s (92.4 kB/s)
Preconfiguring packages ...

Package configuration






                      lqqqqqqqqqqqqqqqqqqqqqqqqqqqu Postfix Configuration tqqqqqqqqqqqqqqqqqqqqqqqqqqqk
                      x Please select the mail server configuration type that best meets your needs.  x
                      x                                                                               x
                      x  No configuration:                                                            x
                      x   Should be chosen to leave the current configuration unchanged.              x
                      x  Internet site:                                                               x
                      x   Mail is sent and received directly using SMTP.                              x
                      x  Internet with smarthost:                                                     x
                      x   Mail is received directly using SMTP or by running a utility such           x
                      x   as fetchmail. Outgoing mail is sent using a smarthost.                      x
                      x  Satellite system:                                                            x
                      x   All mail is sent to another machine, called a 'smarthost', for delivery.    x
                      x  Local only:                                                                  x
                      x   The only delivered mail is the mail for local users. There is no network.   x
                      x                                                                               x
                      x General type of mail configuration:                                           x
                      x                                                                               x
                      x                            No configuration ←取りあえずここを選択                                  x
                      x                            Internet Site                                      x
                      x                            Internet with smarthost                            x
                      x                            Satellite system                                   x
                      x                            Local only                                         x
                      x                                                                               x
                      x                                                                               x
                      x                      <Ok>                          <Cancel>                     x
                      x                                                                               x
                      mqqqqqqqqqqqqqqqqqqqqqqqqqqqqqqqqqqqqqqqqqqqqqqqqqqqqqqqqqqqqqqqqqqqqqqqqqqqqqqqj







(Reading database ... 14065 files and directories currently installed.)
Removing exim4-daemon-light ...
Stopping MTA:.
ALERT: exim paniclog /var/log/exim4/paniclog has non-zero size, mail system possibly broken ... failed!
Removing exim4-base ...
Removing exim4-config ...
Processing triggers for man-db ...
!Selecting previously deselected package python2.6-minimal.
(Reading database ... 13928 files and directories currently installed.)
Unpacking python2.6-minimal (from .../python2.6-minimal_2.6.6-8+b1_armel.deb) ...
Selecting previously deselected package python2.6.
Unpacking python2.6 (from .../python2.6_2.6.6-8+b1_armel.deb) ...
Selecting previously deselected package python-minimal.
Unpacking python-minimal (from .../python-minimal_2.6.6-3+squeeze7_all.deb) ...
Selecting previously deselected package python.
Unpacking python (from .../python_2.6.6-3+squeeze7_all.deb) ...
Selecting previously deselected package db4.8-util.
Unpacking db4.8-util (from .../db4.8-util_4.8.30-2_armel.deb) ...
Selecting previously deselected package sasl2-bin.
Unpacking sasl2-bin (from .../sasl2-bin_2.1.23.dfsg1-7_armel.deb) ...
Selecting previously deselected package postfix.
Unpacking postfix (from .../postfix_2.7.1-1+squeeze1_armel.deb) ...
Processing triggers for man-db ...
Setting up python2.6-minimal (2.6.6-8+b1) ...
Linking and byte-compiling packages for runtime python2.6...
Setting up python2.6 (2.6.6-8+b1) ...
Setting up python-minimal (2.6.6-3+squeeze7) ...
Setting up python (2.6.6-3+squeeze7) ...
Setting up db4.8-util (4.8.30-2) ...
Setting up sasl2-bin (2.1.23.dfsg1-7) ...
update-rc.d: warning: saslauthd stop runlevel arguments (0 1 6) do not match LSB Default-Stop values (1)
To enable saslauthd, edit /etc/default/saslauthd and set START=yes ... (warning).
Setting up postfix (2.7.1-1+squeeze1) ...
Adding group `postfix' (GID 108) ...
Done.
Adding system user `postfix' (UID 105) ...
Adding new user `postfix' (UID 105) with group `postfix' ...
Not creating home directory `/var/spool/postfix'.
Creating /etc/postfix/dynamicmaps.cf
Adding tcp map entry to /etc/postfix/dynamicmaps.cf
Adding group `postdrop' (GID 109) ...
Done.

Postfix was not set up.  Start with
  cp /usr/share/postfix/main.cf.debian /etc/postfix/main.cf
.  If you need to make changes, edit
/etc/postfix/main.cf (and others) as needed.  To view Postfix configuration
values, see postconf(1).

After modifying main.cf, be sure to run '/etc/init.d/postfix reload'.


root@meckk:~#

root@meckk:~# cp /usr/lib/postfix/main.cf /etc/postfix/main.cf 
root@meckk:~# vi /etc/postfix/main.cf 
# 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/.
#
# For best results, change no more than 2-3 parameters at a time,
# and test if Postfix still works after every change.

# 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/lib/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  コメント削除

# 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 = host.domain.tld
myhostname = mail.meckk.com  ホストネーム記入

# 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 = meckk.com  ドメイン記入

# 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.
#
# Debian GNU/Linux specific:  Specifying a file name will cause the
# first line of that file to be used as the name.  The Debian default
# is /etc/mailname.
#
#myorigin = /etc/mailname
#myorigin = $myhostname
myorigin = $mydomain  コメント削除

# 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  コメント削除
#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.  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  コメント削除
#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
# 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  コメント削除
#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 does 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 = 168.100.189.0/28, 127.0.0.0/8
#mynetworks = $config_directory/mynetworks
#mynetworks = hash:/etc/postfix/network_table
mynetworks = 127.0.0.0/8, 192.168.1.0/24  追記

# 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  コメント削除
#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  コメント削除
#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/  コメント削除

# 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 $parameter substitutions. This is to
# make it easier to specify shell syntax (see example below).
#
# Avoid shell meta characters because they will force Postfix to run
# an expensive shell process. Procmail alone is expensive enough.
#
# IF YOU USE THIS TO DELIVER MAIL SYSTEM-WIDE, YOU MUST SET UP AN
# ALIAS THAT FORWARDS MAIL FOR ROOT TO A REAL USER.
#
#mailbox_command = /usr/bin/procmail
#mailbox_command = /usr/bin/procmail -a "$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".
#
#mailbox_transport = lmtp:unix:/file/name
#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  コメント削除
body_checks = regexp:/etc/postfix/body_checks   追加

# 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)
#smtpd_banner = $myhostname ESMTP $mail_name (@@DISTRO@@)  コメントアウト
smtpd_banner = $myhostname ESMTP   追加

# 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 sesssion, su root and run "screen -r
# " where  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/postfix  追記

# 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   追記

# mailq_path: The full pathname of the Postfix mailq command.  This
# is the Sendmail-compatible mail queue listing command.
#
mailq_path = /usr/bin/mailq   追記
# 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   追記

# html_directory: The location of the Postfix HTML documentation.
#
#html_directory =  コメントアウト

# manpage_directory: The location of the Postfix on-line manual pages.
#
#manpage_directory =  コメントアウト

# sample_directory: The location of the Postfix sample configuration files.
# This parameter is obsolete as of Postfix 2.1.
#
#sample_directory =  コメントアウト

# readme_directory: The location of the Postfix README files.
#
#readme_directory =  コメントアウト
以下追記
message_size_limit = 10485760
mailbox_size_limit = 1073741824

smtpd_sasl_type = dovecot
smtpd_sasl_path = private/auth-client
smtpd_sasl_auth_enable = yes
smtpd_sasl_security_options = noanonymous
smtpd_sasl_local_domain = $myhostname
smtpd_client_restrictions = permit_mynetworks,reject_unknown_client,permit
smtpd_recipient_restrictions = permit_mynetworks,permit_auth_destination,permit_sasl_authenticated,reject



root@meckk:~# vi /etc/postfix/header_checks 

/^From:.*<#.*@.*>/ REJECT
/^Return-Path:.*<#.*@.*>/ REJECT


root@meckk:~# vi /etc/postfix/body_checks 

/^(|[^>].*)example.com/ REJECT


root@meckk:~# newaliases 
root@meckk:~#

root@meckk:~# /etc/init.d/postfix restart 
Stopping Postfix Mail Transport Agent: postfix.
Starting Postfix Mail Transport Agent: postfix.
root@meckk:~#

root@meckk:~# aptitude -y install dovecot-common dovecot-pop3d dovecot-imapd 
The following NEW packages will be installed:
  dovecot-common dovecot-imapd dovecot-pop3d libpq5{a}
0 packages upgraded, 4 newly installed, 0 to remove and 0 not upgraded.
Need to get 7373 kB of archives. After unpacking 14.3 MB will be used.
Get:1 http://ftp.riken.jp/Linux/debian/debian/ squeeze/main dovecot-common armel 1:1.2.15-7 [5077 kB]
Get:2 http://security.debian.org/ squeeze/updates/main libpq5 armel 8.4.12-0squeeze1 [157 kB]
Get:3 http://ftp.riken.jp/Linux/debian/debian/ squeeze/main dovecot-imapd armel 1:1.2.15-7 [1117 kB]
Get:4 http://ftp.riken.jp/Linux/debian/debian/ squeeze/main dovecot-pop3d armel 1:1.2.15-7 [1023 kB]
Fetched 7373 kB in 1min 19s (92.4 kB/s)
Selecting previously deselected package libpq5.
(Reading database ... 14931 files and directories currently installed.)
Unpacking libpq5 (from .../libpq5_8.4.12-0squeeze1_armel.deb) ...
Selecting previously deselected package dovecot-common.
Unpacking dovecot-common (from .../dovecot-common_1%3a1.2.15-7_armel.deb) ...
Selecting previously deselected package dovecot-imapd.
Unpacking dovecot-imapd (from .../dovecot-imapd_1%3a1.2.15-7_armel.deb) ...
Selecting previously deselected package dovecot-pop3d.
Unpacking dovecot-pop3d (from .../dovecot-pop3d_1%3a1.2.15-7_armel.deb) ...
Processing triggers for man-db ...
Setting up libpq5 (8.4.12-0squeeze1) ...
Setting up dovecot-common (1:1.2.15-7) ...

Creating config file /etc/dovecot/dovecot.conf with new version

Creating config file /etc/dovecot/dovecot-ldap.conf with new version

Creating config file /etc/dovecot/dovecot-sql.conf with new version
Creating generic self-signed certificate: /etc/ssl/certs/dovecot.pem
This certificate will expire in 10 years.
(replace with hand-crafted or authorized one if needed).
hostname: Name or service not known
WARNING: Could not get FQDN, using "meckk".
Starting IMAP/POP3 mail server: dovecot.
Setting up dovecot-imapd (1:1.2.15-7) ...
Restarting IMAP/POP3 mail server: dovecotIf you have trouble with authentication failures,
enable auth_debug setting. See http://wiki.dovecot.org/WhyDoesItNotWork
This message goes away after the first successful login.
.
Setting up dovecot-pop3d (1:1.2.15-7) ...
Restarting IMAP/POP3 mail server: dovecotIf you have trouble with authentication failures,
enable auth_debug setting. See http://wiki.dovecot.org/WhyDoesItNotWork
This message goes away after the first successful login.

root@meckk:~#


root@meckk:~# vi /etc/dovecot/dovecot.conf 
## Dovecot configuration file

# If you're in a hurry, see http://wiki.dovecot.org/QuickConfiguration

# "dovecot -n" command gives a clean output of the changed settings. Use it
# instead of copy&pasting this file when posting to the Dovecot mailing list.

# '#' character and everything after it is treated as comments. Extra spaces
# and tabs are ignored. If you want to use either of these explicitly, put the
# value inside quotes, eg.: key = "# char and trailing whitespace  "

# Default values are shown for each setting, it's not required to uncomment
# those. These are exceptions to this though: No sections (e.g. namespace {})
# or plugin settings are added by default, they're listed only as examples.
# Paths are also just examples with the real defaults being based on configure
# options. The paths listed here are for configure --prefix=/usr
# --sysconfdir=/etc --localstatedir=/var --with-ssldir=/etc/ssl

# Base directory where to store runtime data.
#base_dir = /var/run/dovecot

# Protocols we want to be serving: imap imaps pop3 pop3s managesieve
# If you only want to use dovecot-auth, you can set this to "none".
#protocols = imap imaps
protocols = imap imaps pop3 pop3s

# A space separated list of IP or host addresses where to listen in for
# connections. "*" listens in all IPv4 interfaces. "[::]" listens in all IPv6
# interfaces. Use "*, [::]" for listening both IPv4 and IPv6.
#
# If you want to specify ports for each service, you will need to configure
# these settings inside the protocol imap/pop3/managesieve { ... } section,
# so you can specify different ports for IMAP/POP3/MANAGESIEVE. For example:
#   protocol imap {
#     listen = *:10143
#     ssl_listen = *:10943
#     ..
#   }
#   protocol pop3 {
#     listen = *:10100
#     ..
#   }
#   protocol managesieve {
#     listen = *:12000
#     ..
#   }
#listen = *

# Disable LOGIN command and all other plaintext authentications unless
# SSL/TLS is used (LOGINDISABLED capability). Note that if the remote IP
# matches the local IP (ie. you're connecting from the same computer), the
# connection is considered secure and plaintext authentication is allowed.
disable_plaintext_auth = no  コメントを解除して変更

# Should all IMAP and POP3 processes be killed when Dovecot master process
# shuts down. Setting this to "no" means that Dovecot can be upgraded without
# forcing existing client connections to close (although that could also be
# a problem if the upgrade is eg. because of a security fix). This however
# means that after master process has died, the client processes can't write
# to log files anymore.
#shutdown_clients = yes

##
## Logging
##

# Log file to use for error messages, instead of sending them to syslog.
# /dev/stderr can be used to log into stderr.
#log_path =

# Log file to use for informational and debug messages.
# Default is the same as log_path.
#info_log_path =

# Prefix for each line written to log file. % codes are in strftime(3)
# format.
#log_timestamp = "%b %d %H:%M:%S "
log_timestamp = "%Y-%m-%d %H:%M:%S "

# Syslog facility to use if you're logging to syslog. Usually if you don't
# want to use "mail", you'll use local0..local7. Also other standard
# facilities are supported.
#syslog_facility = mail

##
## SSL settings
##

# IP or host address where to listen in for SSL connections. Remember to also
# add imaps and/or pop3s to protocols setting. Defaults to same as "listen"
# setting if not specified.
#ssl_listen =

# SSL/TLS support: yes, no, required. 
ssl = no

途中省略

mail_location = maildir:~/Maildir

途中省略

mechanisms = plain login

途中省略

# It's possible to export the authentication interface to other programs:
  socket listen {
    #master {
      # Master socket provides access to userdb information. It's typically
      # used to give Dovecot's local delivery agent access to userdb so it
      # can find mailbox locations.
      #path = /var/run/dovecot/auth-master
      #mode = 0600
      # Default user/group is the one who started dovecot-auth (root)
      #user =
      #group =
    #}
    client {
      # The client socket is generally safe to export to everyone. Typical use
      # is to export it to your SMTP server so it can do SMTP AUTH lookups
      # using it.
      path = /var/spool/postfix/private/auth-client
      mode = 0660
      user = postfix
      group = postfix
    }
  }

以下省略
root@meckk:~#


【Tips】
後日、同じような設定でメールサーバーを構築しましたが、接続をしようとすると接続が拒否されましたとかで接続できません。
詳細な内容は、Couldn't open INBOX: Internal error occured. Refer to server log for more information. です。
設定ファイルのどこかを間違えているのだろうと思って、正常に動作している設定ファイルをコピーしても同様です。
更に調べて見ると、接続が出来るユーザーも存在しております。
どこが異なるのかと見ると、接続ができないユーザーには、Maildir が作成されておりません。

新規にユーザーを作成しても自動的に Maildir が作成される様子はありません。 そう言えば Fedora の時も、自動的に作成する操作をした事を思い出しました。( Maildirの自動の作成過程を理解しておりません)
設定は以下の通りです。

root@meckk:~# mkdir -p /etc/skel/Maildir/new
root@meckk:~# mkdir -p /etc/skel/Maildir/cur
root@meckk:~# mkdir -p /etc/skel/Maildir/tmp
root@meckk:~# chmod -R 700 /etc/skel/Maildir/

上の3つは、以下のようにまとめて書くことも出来るようです。
mkdir -p /etc/skel/Maildir/{new,cur,tmp}
既存のユーザーには適応しませんので、一度削除してから、再度ユーザーを作成しました。(大量の場合はスクリプトも多く発表されております)
root@meckk:~# userdel -r yukke
root@meckk:~# adduser --home /home/yukke_no_kobeya/yukke --ingroup yukke_no_kobeya yukke
やり方は、こんな感じです。
それから私の環境だけの現象と思いますが、サーバーの電源を切るとdovecotが自動的に立ち上がりません。
自動起動の設定にはしているのですが、停電などがあるとメールの受信が出来なくなってしまいます。
結局は、下記のように再起動をして対処しています。
root@meckk;~# /etc/init.d/dovecot restart
Restarting IMAP/POP3 mail server: dovecot. と出るのが普通の状態ですが、
Dovecot Imap を停止中: [失敗]
Dovecot Imap を起動中: Last died with error (see error log for more information): Time just moved backwards by 700 seconds. This might cause a lot of problems, so I'll just kill myself now. http://wiki.dovecot.org/TimeMovedBackwards
[ OK ]
cause a lot of problems と言われても分かりませんし、停電は年間数回あるかないかですので、この現象には対策せず放置しています。

メールサーバーやメールアドレスを公開すると、迷惑メールや不正中継の試みが山のように来ます。
それも100や200の単位ではなくて、一日に数千になる場合もあるから驚きです。
自動で発行しているから、数などはどうにでもなるのでしょう。
本当に迷惑以外の何物でもないです。
メールの不正中継に使用する名前で、私のサイトが攻撃を受ける名前で特に多いのをピックアップしました。
password、password123、123123、123456、a1b2c3d4、abuse、access、account、accounts、action
admin、administrator、badboy、base、billing、bitch、bonjour、boston、bunchchubby、careers
changer、client、cmroberts、cocacola、coffe、coleallure、collections、communication、compaq、connecte
contact、Contact、contacter、cookie、cooper、copie、coupon、cowboy、cr、curchn
cynthia.hill、cypher1、daemon、dam.mcfarland、dbrunsonjn、ddaniel、de、design、destroyer、developpement
digital、dignatows、documentation、dotardly、download、dragon、dreams、drj、dullin、ebowbelfer
eclean、 eddysanfordgi、 editor、 email、 employment、 entreprise、 environnement、 ertotdd、 etzoa、 eva
evengage、 falamejark、 fantundeluna、 fax、 firewall、 fontenot、 foodp、 forever、 forum
forums、 fremigia、 fuckme、 fuckyou、 fucs、 fumiko、 futoma、 gateway、 george
germantax、 gokcesu、 golau、 gunn、 harbin3、 harper、 help、 hero、 home
homepage、 horizon、 hostmaster、 house、 hunter、 image、 images、 info、 invite
java、 killer、 langue、 library、 linux、 locale、 love、 mail、 manager
master、 matrix、 menu、 monkey、 msfadmin、 music、 mysql、 news、 noauth
noreply、 office、 operator、 photo、 photos、 pop3、 postmaster、 princess、 proxy
psycho、 qwerty1、 ranger、 records、 reply、 root、 sales、 secret、 session
sessions、 sexysexy、 simon、 spam、 spameri、 staff、 statistiques、 student、 success
sunshine、 superman、 support、 sysadmin、 test123、 test、 toor、 transferred、 united
unwrap、 utilization、 visitor、 warrior、 web、 webmaster、 welcome、 winner、 www、 zero
特に多いのをピックアップしましたが、実際には更に数倍の名前が使われております。
少なくとも、上記に記載されている名前だけは、メールアドレスには使用しない方が無難です。
使用すると、即刻感知され、メールの中継アドレスとして利用される危険があります。