postfix メールサーバ

参考サイト

電子メールプロトコル再入門

検証環境

$ uname -a Linux ns1 4.18.0-372.9.1.el8.x86_64 #1 SMP Fri Apr 15 22:12:19 EDT 2022 x86_64 x86_64 x86_64 GNU/Linux $ cat /etc/redhat-release Red Hat Enterprise Linux release 8.6 (Ootpa)
$ sudo dnf --disablerepo=* info postfix サブスクリプション管理リポジトリーを更新しています。 コンシューマー識別子を読み込めません このシステムは、エンタイトルメントサーバーに登録されていません。subscription-manager で登録できます。 インストール済みパッケージ 名前 : postfix エポック : 2 バージョン : 3.5.8 リリース : 4.el8 Arch : x86_64 サイズ : 4.3 M ソース : postfix-3.5.8-4.el8.src.rpm リポジトリー : @System repo から : InstallMedia-BaseOS 概要 : Postfix Mail Transport Agent URL : http://www.postfix.org ライセンス : (IBM and GPLv2+) or (EPL-2.0 and GPLv2+) 説明 : Postfix is a Mail Transport Agent (MTA).

構成

設定ファイル

設定反映コマンド /usr/sbin/postmap /etc/postfix/transport

コマンド

Postfixのデフォルト設定値

postconf -d

EHLO, HELO

メール中継ログ

中継が成功。250 2.0.0 Ok: queued as XXXXXXXXXXX

Aug 30 22:09:01 ns2 postfix/smtpd[3374]: connect from rhel00.wakuwakuoyaji.xyz[192.168.195.150] Aug 30 22:09:18 ns2 postfix/smtpd[3374]: 02C1B188BD01: client=rhel00.wakuwakuoyaji.xyz[192.168.195.150] Aug 30 22:09:25 ns2 postfix/cleanup[3375]: 02C1B188BD01: message-id=<> Aug 30 22:09:25 ns2 postfix/qmgr[3364]: 02C1B188BD01: from=<test@hoge.com>, size=225, nrcpt=1 (queue active) Aug 30 22:09:25 ns2 postfix/smtp[3366]: 02C1B188BD01: to=<test@test.example.com>, relay=192.168.195.100[192.168.195.100]:25, delay=15, delays=15/0/0.03/0.01, dsn=2.0.0, status=sent (250 2.0.0 Ok: queued as 87F6E8CB4A1) Aug 30 22:09:25 ns2 postfix/qmgr[3364]: 02C1B188BD01: removed

リレー拒否

main.cf の mynetworks に指定したIPアドレス以外からメールの送信があった場合、Relay access deniedとなる。

ug 30 22:08:13 ns2 postfix/smtp[3369]: 1E8DA188BD01: to=<test@test.example.com>, relay=192.168.195.100[192.168.195.100]:25, delay=516, delays=516/0.11/0.12/0.01, dsn=2.0.0, status=sent (250 2.0.0 Ok: queued as 4C7E58CB4A0) Aug 30 22:08:13 ns2 postfix/qmgr[3364]: 1E8DA188BD01: removed Aug 30 22:08:17 ns2 postfix/smtpd[3371]: connect from localhost[::1] Aug 30 22:08:52 ns2 postfix/smtpd[3371]: NOQUEUE: reject: RCPT from localhost[::1]: 454 4.7.1 <test@test.example.com>: Relay access denied; from=<test@hoge.com> to=<test@test.example.com> proto=SMTP helo=<postfix>

/etc/postfix/main.cf ファイル

デフォルト設定 デフォルトでは25番ポートだけがあいている。

# # Postfix master process configuration file. For details on the format # of the file, see the master(5) manual page (command: "man 5 master" or # on-line: http://www.postfix.org/master.5.html). # # Do not forget to execute "postfix reload" after editing this file. # # ========================================================================== # service type private unpriv chroot wakeup maxproc command + args # (yes) (yes) (no) (never) (100) # ========================================================================== smtp inet n - n - - smtpd #smtp inet n - n - 1 postscreen #smtpd pass - - n - - smtpd #dnsblog unix - - n - 0 dnsblog #tlsproxy unix - - n - 0 tlsproxy #submission inet n - n - - smtpd # -o syslog_name=postfix/submission # -o smtpd_tls_security_level=encrypt # -o smtpd_sasl_auth_enable=yes # -o smtpd_tls_auth_only=yes # -o smtpd_reject_unlisted_recipient=no # -o smtpd_client_restrictions=$mua_client_restrictions # -o smtpd_helo_restrictions=$mua_helo_restrictions # -o smtpd_sender_restrictions=$mua_sender_restrictions # -o smtpd_recipient_restrictions= # -o smtpd_relay_restrictions=permit_sasl_authenticated,reject # -o milter_macro_daemon_name=ORIGINATING #smtps inet n - n - - smtpd # -o syslog_name=postfix/smtps # -o smtpd_tls_wrappermode=yes # -o smtpd_sasl_auth_enable=yes # -o smtpd_reject_unlisted_recipient=no # -o smtpd_client_restrictions=$mua_client_restrictions # -o smtpd_helo_restrictions=$mua_helo_restrictions # -o smtpd_sender_restrictions=$mua_sender_restrictions # -o smtpd_recipient_restrictions= # -o smtpd_relay_restrictions=permit_sasl_authenticated,reject # -o milter_macro_daemon_name=ORIGINATING #628 inet n - n - - qmqpd pickup unix n - n 60 1 pickup cleanup unix n - n - 0 cleanup qmgr unix n - n 300 1 qmgr #qmgr unix n - n 300 1 oqmgr tlsmgr unix - - n 1000? 1 tlsmgr rewrite unix - - n - - trivial-rewrite bounce unix - - n - 0 bounce defer unix - - n - 0 bounce trace unix - - n - 0 bounce verify unix - - n - 1 verify flush unix n - n 1000? 0 flush proxymap unix - - n - - proxymap proxywrite unix - - n - 1 proxymap smtp unix - - n - - smtp relay unix - - n - - smtp -o syslog_name=postfix/$service_name # -o smtp_helo_timeout=5 -o smtp_connect_timeout=5 showq unix n - n - - showq error unix - - n - - error retry unix - - n - - error discard unix - - n - - discard local unix - n n - - local virtual unix - n n - - virtual lmtp unix - - n - - lmtp anvil unix - - n - 1 anvil scache unix - - n - 1 scache postlog unix-dgram n - n - 1 postlogd # # ==================================================================== # Interfaces to non-Postfix software. Be sure to examine the manual # pages of the non-Postfix software to find out what options it wants. # # Many of the following services use the Postfix pipe(8) delivery # agent. See the pipe(8) man page for information about ${recipient} # and other message envelope options. # ==================================================================== # # maildrop. See the Postfix MAILDROP_README file for details. # Also specify in main.cf: maildrop_destination_recipient_limit=1 # #maildrop unix - n n - - pipe # flags=DRXhu user=vmail argv=/usr/local/bin/maildrop -d ${recipient} # # ==================================================================== # # Recent Cyrus versions can use the existing "lmtp" master.cf entry. # # Specify in cyrus.conf: # lmtp cmd="lmtpd -a" listen="localhost:lmtp" proto=tcp4 # # Specify in main.cf one or more of the following: # mailbox_transport = lmtp:inet:localhost # virtual_transport = lmtp:inet:localhost # # ==================================================================== # # Cyrus 2.1.5 (Amos Gouaux) # Also specify in main.cf: cyrus_destination_recipient_limit=1 # #cyrus unix - n n - - pipe # flags=DRX user=cyrus argv=/usr/lib/cyrus-imapd/deliver -e -r ${sender} -m ${extension} ${user} # # ==================================================================== # # Old example of delivery via Cyrus. # #old-cyrus unix - n n - - pipe # flags=R user=cyrus argv=/usr/lib/cyrus-imapd/deliver -e -m ${extension} ${user} # # ==================================================================== # # See the Postfix UUCP_README file for configuration details. # #uucp unix - n n - - pipe # flags=Fqhu user=uucp argv=uux -r -n -z -a$sender - $nexthop!rmail ($recipient) # # ==================================================================== # # Other external delivery methods. # #ifmail unix - n n - - pipe # flags=F user=ftn argv=/usr/lib/ifmail/ifmail -r $nexthop ($recipient) # #bsmtp unix - n n - - pipe # flags=Fq. user=bsmtp argv=/usr/local/sbin/bsmtp -f $sender $nexthop $recipient # #scalemail-backend unix - n n - 2 pipe # flags=R user=scalemail argv=/usr/lib/scalemail/bin/scalemail-store # ${nexthop} ${user} ${extension} # #mailman unix - n n - - pipe # flags=FRX user=list argv=/usr/lib/mailman/bin/postfix-to-mailman.py # ${nexthop} ${user}

submission ポートを有効化

# diff -c /etc/postfix/master.cf.orig /etc/postfix/master.cf *** /etc/postfix/master.cf.orig 2022-02-17 18:06:01.000000000 -0500 --- /etc/postfix/master.cf 2022-04-29 16:18:22.675925641 -0400 *************** *** 14,20 **** #smtpd pass - - n - - smtpd #dnsblog unix - - n - 0 dnsblog #tlsproxy unix - - n - 0 tlsproxy ! #submission inet n - n - - smtpd # -o syslog_name=postfix/submission # -o smtpd_tls_security_level=encrypt # -o smtpd_sasl_auth_enable=yes --- 14,20 ---- #smtpd pass - - n - - smtpd #dnsblog unix - - n - 0 dnsblog #tlsproxy unix - - n - 0 tlsproxy ! submission inet n - n - - smtpd # -o syslog_name=postfix/submission # -o smtpd_tls_security_level=encrypt # -o smtpd_sasl_auth_enable=yes