配置 postfix 以在 Google Compute Engine 实例中使用 Google Apps SMTP 中继

Question 1

使用安装 postfix apt-get install postfix。当系统询问时，请选择“卫星系统”或带有智能主机的选项。其他的暂时接受默认设置。

根据以下文件编辑你的 main.cf：

/etc/postfix/main.cf

# a file which should contain the google apps domain
myorigin = /etc/mailname
# if your google apps domain is in mydestination, remove it, or postfix will attempt to deliver your mail locally
mydestination = ...., localhost

# Google Apps Relay SMTP, must use Port 587 because, 25 is blocked
relayhost = [smtp-relay.gmail.com]:587

# Force ehlo behavior
smtp_always_send_ehlo = yes
smtp_helo_name = <yourappsdomainhere>

# Enable TLS
smtp_use_tls=yes
smtp_tls_CAfile = /etc/ssl/certs/ca-certificates.crt

# limit smtp to loopback interface & compute engine doesn't support ipv6
inet_interfaces = loopback-only
inet_protocols = ipv4

# These lines can be used, if the result is not as expected
# debug_peer_list = smtp-relay.gmail.com
# debug_peer_level = 2

使用重启 postfix service postfix restart。一切应该都很好。

这可能不是最干净的解决方案，但对我来说还是有效的。

Answer

使用安装 postfix apt-get install postfix。当系统询问时，请选择“卫星系统”或带有智能主机的选项。其他的暂时接受默认设置。

根据以下文件编辑你的 main.cf：

/etc/postfix/main.cf

# a file which should contain the google apps domain
myorigin = /etc/mailname
# if your google apps domain is in mydestination, remove it, or postfix will attempt to deliver your mail locally
mydestination = ...., localhost

# Google Apps Relay SMTP, must use Port 587 because, 25 is blocked
relayhost = [smtp-relay.gmail.com]:587

# Force ehlo behavior
smtp_always_send_ehlo = yes
smtp_helo_name = <yourappsdomainhere>

# Enable TLS
smtp_use_tls=yes
smtp_tls_CAfile = /etc/ssl/certs/ca-certificates.crt

# limit smtp to loopback interface & compute engine doesn't support ipv6
inet_interfaces = loopback-only
inet_protocols = ipv4

# These lines can be used, if the result is not as expected
# debug_peer_list = smtp-relay.gmail.com
# debug_peer_level = 2

使用重启 postfix service postfix restart。一切应该都很好。

这可能不是最干净的解决方案，但对我来说还是有效的。

Question 2

我在互联网上搜索了几天才找到你和我正在寻找的解决方案。

确保您已在 Google Apps 帐户中的“应用”>“Google Apps”>“Gmail”>“高级设置”下设置了 SMTP 中继设置，如下所示：

确保您已经安装了 postfix 和 libsasl2-modules。

sudo apt-get update
sudo apt-get install postfix
sudo apt-get install libsasl2-modules

Postfix 配置

在 Postfix 配置期间设置以下设置：

常规邮件配置类型：使用智能主机的互联网。
邮件名称：example.com（完全限定域名）
中继主机：[smtp.gmail.com]:587

你的/etc/postfix/main.cf文件看起来应该像这样：

myhostname = yourdomain.com
smtpd_banner = $myhostname ESMTP $mail_name (Debian/GNU)
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

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_relay_restrictions = permit_mynetworks permit_sasl_authenticated defer_unauth_destination
alias_maps = hash:/etc/aliases
alias_database = hash:/etc/aliases

myorigin = /etc/mailname
mydestination = yourdomain.com

relayhost = [smtp.gmail.com]:587
mynetworks = 127.0.0.0/8 [::ffff:127.0.0.0]/104 [::1]/128
mailbox_size_limit = 0
recipient_delimiter = +
inet_interfaces = all

# Use IPv4 protocol
inet_protocols = ipv4

# 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

创建一个/etc/postfix/sasl/passwd文件并添加您的 Google Apps 用户名和密码，如下所示：

[smtp.gmail.com]:587 [email protected]:yourpassword

现在通过运行 postmap 命令为 Postfix 创建哈希数据库文件：

sudo postmap /etc/postfix/sasl/passwd

保护你的密码和哈希数据库文件，以便只有 root 可以读取和写入它们：

sudo chown root:root /etc/postfix/sasl/passwd /etc/postfix/sasl/passwd.db
sudo chmod 0600 /etc/postfix/sasl/passwd /etc/postfix/sasl/passwd.db

通过以下方式重新启动 Postfix：

sudo /etc/init.d/postfix restart

如果你已经安装了 mailutils，你可以通过以下方式测试发送邮件：

echo "body of your email" | mail -s "This is a Subject" -a "From: [email protected]" [email protected]

如果您没有收到邮件，请检查您的 mail.log 文件是否有任何错误消息：

sudo tail -f /var/log/mail.log

我写了一篇更详细的文章：http://dev.robbertvermeulen.com/postfix-google-apps-smtp-relay-google-compute-engine/

Answer