メールサーバのパフォーマンステスト、負荷テストで大量にメールを送る方法

大量にメールを送信する方法はいくつかありますが、Postfixの標準機能でも実現できるため、簡単に解説いたします。

コマンドのみ確認

# smtp-source -m 100 -s 10 -l 10000 -S 'test mail' -f relay@test.local -t user01@test.local 192.168.11.11:25

# smtp-sink -u root -c 192.168.11.12:25 100000

メール送信ツール：smtp-source

利用する環境は、先日作成した環境を利用しております。

# which smtp-source  //コマンド確認 Postfixを導入すればセットで導入されているはず
/usr/sbin/smtp-source


# smtp-source -m 100 -s 10 -l 10000 -S 'test mail' -f relay@test.local -t user01@test.local 192.168.11.11:25

上記は、「192.168.11.11:25」に対し、From：relay@test.local、To：user01@test.local、10KBのメールを並列に10セッション利用して、トータルで100通送るテストとなる。

作成した環境は、test.localドメインの場合、192.168.11.12に内部転送する設定になっているため、192.168.11.12にて受信できてれいば、正常に稼働できていることになる。


■内部受信メールサーバ（Maildir形式で保存）
# cd /home/user01/Maildir/new/
# ll | grep pop  //10KBのファイル確認
-rw-------. 1 user01 user01 10465 12月 20 20:20 1639999234.Vfd00Id03015M784267.pop
-rw-------. 1 user01 user01 10465 12月 20 20:20 1639999234.Vfd00Id1a07fM795127.pop
-rw-------. 1 user01 user01 10465 12月 20 20:20 1639999234.Vfd00Id1a148M936597.pop
-rw-------. 1 user01 user01 10465 12月 20 20:20 1639999234.Vfd00Id1a151M960876.pop
-rw-------. 1 user01 user01 10465 12月 20 20:20 1639999235.Vfd00Id1a152M11645.pop
-rw-------. 1 user01 user01 10465 12月 20 20:20 1639999235.Vfd00Id1a153M14606.pop
以下、省略


# ll | grep pop | wc -l  //100通受信できていることを確認
100


# cat 1639999236.Vfd00Ie07413M729612.pop  //適当なファイルを開きFrom、To、Subjectを確認
Return-Path: <relay@test.local>
X-Original-To: user01@test.local
Delivered-To: user01@test.local
Received: from relay.test.local (unknown [192.168.11.11])
        by pop.test.local (Postfix) with ESMTPS id B09218BCBED
        for <user01@test.local>; Mon, 20 Dec 2021 20:20:36 +0900 (JST)
Received: from relay (relay [192.168.11.11])
        by relay.test.local (Postfix) with SMTP id 6AECE988D2C
        for <user01@test.local>; Mon, 20 Dec 2021 20:20:34 +0900 (JST)
From: <relay@test.local>
To: <user01@test.local>
Date: Mon, 20 Dec 2021 20:20:33 +0900 (JST)
Message-Id: <185f.0006.fffffffc@relay>
Subject: test mail

1XXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXX
2XXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXX
3XXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXX

メール受信ツール：smtp-sink

smtp-sourceで大量にメールを送っても、受信側が処理しきれないこともあるため、受信メールを即破棄する際にも利用できるツールです。以下は、192.168.11.11から転送されてきたメールを即破棄しております。受信数（破棄数）を確認できるため「-c」オプションをつけると良いです。

# which smtp-sink  //コマンド確認 Postfixを導入すればセットで導入されているはず
/usr/sbin/smtp-sink


# time smtp-source -m 1000 -s 10 -l 10000 -S 'test mail' -f relay@test.local -t user01@test.local 192.168.11.11:25  //100通だとすぐに送信できてしまうため、1000通に変更

real    0m4.681s
user    0m0.050s
sys     0m0.141s


# smtp-sink -u root -c 192.168.11.12:25 100000
sess=784 quit=778 mesg=1000  //mesgで1000通受信したことを確認できる

マニュアル

smtp-source、smtp-sinkの詳細は、manからも確認可能です。

SMTP-SOURCE(1)                            General Commands Manual                           SMTP-SOURCE(1)

NAME
       smtp-source - parallelized SMTP/LMTP test generator

SYNOPSIS
       smtp-source [options] [inet:]host[:port]

       smtp-source [options] unix:pathname

DESCRIPTION
       smtp-source  connects  to the named host and TCP port (default: port 25) and sends one or more mes‐
       sages to it, either sequentially or in parallel. The program speaks either SMTP (default) or  LMTP.
       Connections can be made to UNIX-domain and IPv4 or IPv6 servers.  IPv4 and IPv6 are the default.

       Note:  this  is  an  unsupported test program. No attempt is made to maintain compatibility between
       successive versions.

       Arguments:

       -4     Connect to the server with IPv4. This option has no effect when  Postfix  is  built  without
              IPv6 support.

       -6     Connect  to the server with IPv6. This option is not available when Postfix is built without
              IPv6 support.

       -A     Don't abort when the server sends something other than the expected positive reply code.

       -c     Display a running counter that is incremented each time an SMTP DATA command completes.

       -C count
              When a host sends RESET instead of SYN|ACK, try count times before giving  up.  The  default
              count is 1. Specify a larger count in order to work around a problem with TCP/IP stacks that
              send RESET when the listen queue is full.

       -d     Don't disconnect after sending a message; send the next message over the same connection.

       -f from
              Use the specified sender address (default: <foo@myhostname>).

       -F file
              Send the pre-formatted message header and body in the specified file, while  prepending  '.'
              before lines that begin with '.', and while appending CRLF after each line.

       -l length
              Send length bytes as message payload. The length does not include message headers.

       -L     Speak LMTP rather than SMTP.

       -m message_count
              Send the specified number of messages (default: 1).

       -M myhostname
              Use  the  specified  hostname or [address] in the HELO command and in the default sender and
              recipient addresses, instead of the machine hostname.

       -N     Prepend a non-repeating sequence number to each recipient address. This avoids  the  artifi‐

SMTP-SINK(1)                              General Commands Manual                             SMTP-SINK(1)

NAME
       smtp-sink - parallelized SMTP/LMTP test server

SYNOPSIS
       smtp-sink [options] [inet:][host]:port backlog

       smtp-sink [options] unix:pathname backlog

DESCRIPTION
       smtp-sink listens on the named host (or address) and port.  It takes SMTP messages from the network
       and throws them away.  The purpose is to measure client performance, not protocol compliance.

       smtp-sink may also be configured to capture each mail delivery  transaction  to  file.  Since  disk
       latencies  are large compared to network delays, this mode of operation can reduce the maximal per‐
       formance by several orders of magnitude.

       Connections can be accepted on IPv4 or IPv6 endpoints, or on UNIX-domain sockets.   IPv4  and  IPv6
       are the default.  This program is the complement of the smtp-source(1) program.

       Note:  this  is  an  unsupported test program. No attempt is made to maintain compatibility between
       successive versions.

       Arguments:

       -4     Support IPv4 only. This option has no effect when Postfix is built without IPv6 support.

       -6     Support IPv6 only. This option is not available when Postfix is built without IPv6 support.

       -8     Do not announce 8BITMIME support.

       -a     Do not announce SASL authentication support.

       -A delay
              Wait delay seconds after responding to DATA, then abort prematurely with a 550 reply status.
              Do  not read further input from the client; this is an attempt to block the client before it
              sends ".".  Specify a zero delay value to abort immediately.

       -b soft-bounce-reply
              Use soft-bounce-reply for soft reject responses.  The default reply  is  "450  4.3.0  Error:
              command failed".

       -B hard-bounce-reply
              Use  hard-bounce-reply  for  hard  reject responses.  The default reply is "500 5.3.0 Error:
              command failed".

       -c     Display running counters that are updated whenever an SMTP session ends, a QUIT  command  is
              executed, or when "." is received.

       -C     Disable XCLIENT support.

       -d dump-template
              Dump  each  mail transaction to a single-message file whose name is created by expanding the
              dump-template via strftime(3) and appending a  pseudo-random  hexadecimal  number  (example:
              "%Y%m%d%H/%M." expands into "2006081203/05.809a62e3").  If the template contains "/" charac‐
              ters, missing directories are created automatically.  The message dump format  is  described