配置 postfix 以使用外部 smtp 服务器

Question

我正在尝试将 postfix 配置为使用外部 smtp 服务器。我已设法将其配置为从 root@host-name 发送电子邮件，但我希望能够从我的域发送它。我关注了this tutorial，还添加了smtp_generic_maps，但它不起作用。
这是我的配置：

# See /usr/share/postfix/main.cf.dist for a commented, more complete version


# Debian 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

smtpd_banner = $myhostname ESMTP $mail_name (Ubuntu)
biff = no

# appending .domain is the MUA's job.
append_dot_mydomain = no

# Uncomment the next line to generate "delayed mail" warnings
#delay_warning_time = 4h

#delay_warning_time = 4h

readme_directory = no

# TLS parameters
smtpd_tls_cert_file=/etc/ssl/certs/ssl-cert-snakeoil.pem
smtpd_tls_key_file=/etc/ssl/private/ssl-cert-snakeoil.key
smtpd_use_tls=yes
smtpd_tls_session_cache_database = btree:${data_directory}/smtpd_scache
smtp_tls_session_cache_database = btree:${data_directory}/smtp_scache
smtpd_tls_security_level=may
smtpd_tls_protocols = !SSLv2, !SSLv3
# See /usr/share/doc/postfix/TLS_README.gz in the postfix-doc package for
# information on enabling SSL in the smtp client.

smtpd_relay_restrictions = permit_mynetworks permit_sasl_authenticated defer_unauth_destination
myhostname = aba-elearning.com
#ABA.Moodle
alias_maps = hash:/etc/aliases
alias_database = hash:/etc/aliases
myorigin = /etc/mailname
mydestination = $myhostname, localhost
relayhost =
mynetworks = 127.0.0.0/8 [::ffff:127.0.0.0]/104 [::1]/128
mailbox_command = procmail -a "$EXTENSION"
mailbox_size_limit = 0
recipient_delimiter = +
inet_interfaces = all
inet_protocols = all
milter_protocol = 2
milter_default_action = accept
smtpd_milters = inet:localhost:12301
non_smtpd_milters = inet:localhost:12301




# enable SASL authentication
smtp_sasl_auth_enable = yes
# disallow methods that allow anonymous authentication.
smtp_sasl_security_options = noanonymous
# where to find sasl_passwd
smtp_sasl_password_maps = hash:/etc/postfix/sasl_passwd
# Enable STARTTLS encryption
smtp_use_tls = yes
# where to find CA certificates
smtp_tls_CAfile = /etc/ssl/certs/ca-certificates.crt

smtp_generic_maps = hash:/etc/postfix/generic

Answer 1

外部 SMTP 服务器配置

1. 转到 sendgrid 和 register 个人资料
2. 转到Sender Authentication 并创建一个新发件人 (Picture)
   指定一些非免费邮箱（我使用的是 office 365 Online 帐号），以便 SendGrid 验证发件人。
3. 检查您的邮箱并点击信中的验证单一发件人按钮 (Picture)
4. 转到SMTP Relay integration page并创建一个apikey，您将放入postfix的sasl_passwd文件（Picture）。在您将其插入并验证之前，请勿关闭验证页面。

后缀配置：

安装一些包和configure postfix:

sudo apt install postfix mailutils

接下来配置/etc/postfix/main.cf文件，添加或修改下一行：

smtpd_banner = $myhostname ESMTP $mail_name (Ubuntu)
biff = no
append_dot_mydomain = no
compatibility_level = 2
smtpd_tls_cert_file=/etc/ssl/certs/ssl-cert-snakeoil.pem
smtpd_tls_key_file=/etc/ssl/private/ssl-cert-snakeoil.key
smtpd_tls_security_level=may

smtp_tls_CApath=/etc/ssl/certs
smtp_tls_security_level=encrypt
smtp_tls_session_cache_database = btree:${data_directory}/smtp_scache

smtpd_relay_restrictions = permit_mynetworks permit_sasl_authenticated defer_unauth_destination
myhostname = localhost.localdomain

alias_maps = hash:/etc/aliases
alias_database = hash:/etc/aliases
myorigin = test
mydestination = $myhostname, localhost
relayhost = [smtp.sendgrid.net]:587
smtp_sasl_auth_enable = yes
smtp_sasl_password_maps = hash:/etc/postfix/sasl_passwd
smtp_sasl_tls_security_options = noanonymous

创建/etc/postfix/sasl_passwd文件（进一步获取api秘钥）：

[smtp.sendgrid.net]:587 apikey:SG.kjaksdjkfajskdk_ASDk.lkjaoIO_Kjkoaofs3i99asfd_kkjasdof99882348IKII

应用设置：

sudo postmap /etc/postfix/sasl_passwd
sudo systemctl restart postfix

在 SendGrid 验证期间测试电子邮件发送

1. 单击下一步验证集成按钮。您将进入让我们测试您的集成页面。

2. 单击验证集成按钮

3. 使用journalctl -f 命令运行不同的终端窗口以查看日志

4. 在终端中运行命令以测试邮件发送，使用 外部 SMTP 服务器配置部分中创建的 -r 参数后的 Single Sender。

    echo "Test Email message body" | mail -r xxxx@yyyy.onmicrosoft.com -s "Email test subject" zzzz@gmail.com
   

结果，我的 gmail.com 邮箱收到了一封测试信。我也将它发送到我的 yahoo.com 邮件地址，并且在延迟一段时间后它也已放入垃圾邮件文件夹。最好不要在雅虎上使用这种方法，因为它不可靠。 “十年”内将不会检索重要通知。

接下来配置/usr/local/nagios/etc/objects/commands.cfg：

define command {
    command_name    notify-service-by-email
    command_line    /usr/bin/printf "%b" "***** Nagios *****\n\nNotification Type: $NOTIFICATIONTYPE$\n\nService: $SERVICEDESC$\nHost: $HOSTALIAS$\nAddress: $HOSTADDRESS$\nState: $SERVICESTATE$\n\nDate/Time: $LONGDATETIME$\n\nAdditional Info:\n\n$SERVICEOUTPUT$\n" | /usr/bin/mail -r xxxx@yyyy.onmicrosoft.com -s "** $NOTIFICATIONTYPE$ Service Alert: $HOSTALIAS$/$SERVICEDESC$ is $SERVICESTATE$ **" $CONTACTEMAIL$
}

这里我将/usr/sbin/sendmail 替换为/usr/bin/mail -r xxxx@yyyy.onmicrosoft.com