Ensure the iptables is initialized with your new configurations when the virtual machine reboots and not with the default setup. You can issue the following commands to save the firewall rules.

确保iptables在虚拟机重启时用新配置而不是默认设置进行初始化。

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An attacker may attempt to change firewall rules or remove logs to cover their tracks.

FORBES: Reduce Policy Complications to Enhance Security

By examining the firewall logs, which are a record of every attempt to connect, those that are dropped and those that are allowed, it is possible to compare them to the firewall policy and discover unused rules.

FORBES: Reduce Policy Complications to Enhance Security

When deploying a new internal application, network, or server, several new rules have to be added to the firewall.

FORBES: Reduce Policy Complications to Enhance Security