1.1 服务器要求

• 云服务器配置：建议至少2核CPU/4GB内存/50GB存储
• 系统选择：Ubuntu 20.04 LTS或CentOS 8
• 网络要求：固定公网IP，推荐配置反向DNS解析

1.2 域名配置

需提前准备：

1. 已注册的域名（如yourdomain.com）
2. 配置MX记录指向服务器IP
3. 设置SPF/DKIM/DMARC记录增强邮件可信度

2.1 Postfix安装配置

# Ubuntu/Debian
sudo apt update
sudo apt install postfix mailutils

# CentOS/RHEL
sudo yum install postfix cyrus-sasl-plain

主要配置文件/etc/postfix/main.cf关键参数：

myhostname = mail.yourdomain.com
mydomain = yourdomain.com
myorigin = $mydomain
inet_interfaces = all
mydestination = $myhostname, localhost.$mydomain, localhost, $mydomain
relayhost =
mynetworks = 127.0.0.0/8
home_mailbox = Maildir/

2.2 Dovecot安装

# Ubuntu
sudo apt install dovecot-core dovecot-imapd dovecot-pop3d

# CentOS
sudo yum install dovecot

3.1 SSL证书配置

使用Let’s Encrypt免费证书：

sudo apt install certbot
sudo certbot certonly --standalone -d mail.yourdomain.com

3.2 防垃圾邮件设置

• 安装SpamAssassin：sudo apt install spamassassin spamc
• 配置Postgrey延迟验证：sudo apt install postgrey

4.1 Roundcube安装

sudo apt install roundcube roundcube-mysql roundcube-plugins

4.2 Nginx配置示例

server {
    listen 443 ssl;
    server_name webmail.yourdomain.com;
    
    ssl_certificate /etc/letsencrypt/live/mail.yourdomain.com/fullchain.pem;
    ssl_certificate_key /etc/letsencrypt/live/mail.yourdomain.com/privkey.pem;
    
    root /usr/share/roundcube;
    index index.php;
    
    location / {
        try_files $uri $uri/ /index.php?$args;
    }
    
    location ~ \.php$ {
        include snippets/fastcgi-php.conf;
        fastcgi_pass unix:/var/run/php/php7.4-fpm.sock;
    }
}

5.1 邮件发送失败排查

• 检查/var/log/mail.log日志
• 测试端口开放：telnet yourserver.com 25
• 验证DNS记录：dig MX yourdomain.com

5.2 性能优化建议

1. 启用邮件队列处理：sudo postconf -e "default_process_limit = 100"
2. 配置Redis缓存：sudo apt install dovecot-redis
3. 限制附件大小：message_size_limit = 20480000