在 AWS 中的 EC2 上配置防火墙

Question

Few days ago I configured firewall on EC2 in AWS. But, the problem was when I configure firewall in EC2, that server went down. Then when I remove this firewall, then the server went up again. but after restarting the server, it was down. then when I disabled firewall from the server it gone up, then remains ok also after restarting further. My question is should we avoid firewall installing on aws EC2?, as the firewall is automatically configured by aws instance. but won't it increase the security by configuring firewall. Did, I do something wrong like double layer protection by installing firewall?

Answer 1

Enabling the Firewall/Security Groups/ does not DOWN the server, it is still up and running but maybe inaccessible to you, as you might have locked yourself from it.

This is exactly the reason why the EC2 Security Groups are there, so you can block access to specific ports and allow access only from specific ports for management, and/or open public access to Web services for example.. if you are building a webserver.

Firewalls can be dangerous if you do not know what you are doing.

If you locked yourself out, then Yes you did something wrong. If you first allow your IP in the firewall, then you will still be able to manage or access it, once the Firewall is up.