VPS 数据库外连接优化指南

在虚拟专有服务（VPS）环境中，数据库外连接是连接到远程数据库的关键步骤，优化这些连接可以显著提升应用程序的性能和用户体验，以下是一些实用的优化方法和最佳实践。

配置数据库外连接

1 添加数据库IP地址

在VPS的etc/hosts文件中添加数据库IP地址，

host yourdatabase.com
  user youruser
  pass yourpassword
  host yourdatabase.com

2 配置端口转发

使用iptables或firewalld配置端口转发，允许应用程序通过VPS访问数据库。

sudo iptables -t nat -A POSTROUTING -o 2221 -j MASQUERADE
sudo iptables -A FORWARD -i 2221 -j ACCEPT 3306,223
sudo iptables -A FORWARD -i 2221 -j ACCEPT 3389,223
sudo iptables -A FORWARD -i 2221 -j ACCEPT 443
sudo iptables -A FORWARD -i 2221 -j ACCEPT 80
sudo service iptables save
sudo service iptables restart

3 配置NAT规则

在VPS的NAT规则中添加数据库连接：

sudo nano /etc/sysctl.conf
...
netfilter-f Firewall1 {
  add 2221,2221,2221,2221,2221,2221,2221,2221,2221,2221,2221,2221,2221,2221,2221,2221,2221,2221,2221,2221,2221,2221,2221,2221,2221,2221,2221,2221,2221,2221,2221,2221,2221,2221,2221,2221,2221,2221,2221,2221,2221,2221,2221,2221,2221,2221,2221,2221,2221,2221,2221,2221,2221,2221,2221,2221,2221,2221,2221,2221,2221,2221,2221,2221,2221,2221,2221,2221,2221,2221,2221,2221,2221,2221,2221,2221,2221,2221,2221,2221,2221,2221,2221,2221,2221,2221,2221,2221,2221,2221,2221,2221,2221,2221,2221,2221,2221,2221,2221,2221,2221,2221,2221,2221,2221,2221,2221,2221,2221,2221,2221,2221,2221,2221,2221,2221,2221,2221,2221,2221,2221,2221,2221,2221,2221,2221,2221,2221,2221,2221,2221,2221,2221,2221,2221,2221,2221,2221,2221,2221,2221,2221,2221,2221,2221,2221,2221,2221,2221,2221,2221,2221,2221,2221,2221,2221,2221,2221,2221,2221,2221,2221,2221,2221,2221,2221,2221,2221,2221,2221,2221,2221,2221,2221,2221,2221,2221,2221,2221,2221,2221,2221,2221,2221,2221,2221,2221,2221,2221,2221,2221,2221,2221,2221,2221,2221,2221,2221,2221,2221,2221,2221,2221,2221,2221,2221,2221,2221,2221,2221,2221,2221,2221,2221,2221,2221,2221,2221,2221,2221,2221,2221,2221,2221,2221,2221,2221,2221,2221,2221,2221,2221,2221,2221,2221,2221,2221,2221,2221,2221,2221,2221,2221,2221,2221,2221,2221,2221,2221,2221,2221,2221,2221,2221,2221,2221,2221,2221,2221,2221,2221,2221,2221,2221,2221,2221,2221,2221,2221,2221,2221,2221,2221,2221,2221,2221,2221,2221,2221,2221,2221,2221,2221,2221,2221,2221,2221,2221,2221,2221,2221,2221,2221,2221,2221,2221,2221,2221,2221,2221,2221,2221,2221,2221,2221,2221,2221,2221,2221,2221,2221,2221,2221,2221,2221,2221,2221,2221,2221,2221,2221,2221,2221,2221,2221,2221,2221,2221,2221,2221,2221,2221,2221,2221,2221,2221,2221,2221,2221,2221,2221,2221,2221,2221,2221,2221,2221,2221,2221,2221,2221,2221,2221,2221,2221,2221,2221,2221,2221,2221,2221,2221,2221,2221,2221,2221,2221,2221,2221,2221,2221,2221,2221,2221,2221,2221,2221,2221,2221,2221,2221,2221,2221,2221,2221,2221,2221,2221,2221,2221,2221,2221,2221,2221,2221,2221,2221,2221,2221,2221,2221,2221,2221,2221,2221,2221,2221,2221,2221,2221,2221,2221,2221,2221,2221,2221,2221,2221,2221,2221,2221,2221,2221,2221,2221,2221,2221,2221,2221,2221,2221,2221,2221,2221,2221,2221,2221,2221,2221,2221,2221,2221,2221,2221,2221,2221,2221,2221,2221,2221,2221,2221,2221,2221,2221,2221,2221,2221,2221,2221,2221,2221,2221,2221,2221,2221,2221,2221,2221,2221,2221,2221,2221,2221,2221,2221,2221,2221,2221,2221,2221,2221,2221,2221,2221,2221,2221,2221,2221,2221,2221,2221,2221,2221,2221,2221,2221,2221,2221,2221,2221,2221,2221,2221,2221,2221,2221,2221,2221,2221,2221,2221,2221,2221,2221,2221,2221,2221,2221,2221,2221,2221,2221,2221,2221,2221,2221,2221,2221,2221,2221,2221,2221,2221,2221,2221,2221,2221,2221,2221,2221,2221,2221,2221,2221,2221,2221,2221,2221,2221,2221,2221,2221,2221,2221,2221,2221,2221,2221,2221,2221,2221,2221,2221,2221,2221,2221,2221,2221,2221,2221,2221,2221,2221,2221,2221,2221,2221,2221,2221,2221,2221,2221,2221,2221,2221,2221,2221,2221,2221,2221,2221,2221,2221,2221,2221,2221,2221,2221,2221,2221,2221,2221,2221,2221,2221,2221,2221,2221,2221,2221,2221,2221,2221,2221,2221,2221,2221,2221,2221,2221,2221,2221,2221,2221,2221,2221,2221,2221,2221,2221,2221,2221,2221,2221,2221,2221,2221,2221,2221,2221,2221,2221,2221,2221,2221,2221