AWS VPC中基于EC2实例构建IDS->防火墙->服务器服务链可行性咨询

Great question—let’s cut to the chase first: EC2 Traffic Mirroring is designed for monitoring/inspection, not for enforcing a mandatory traffic path like you’re describing. It works by copying traffic from a source instance (or network interface) to a target (like your IDS), but it doesn’t redirect the original traffic flow. So your web server would still receive traffic directly, with a duplicate sent to the IDS for monitoring—this won’t force traffic to go through IDS → Firewall → Web Server in sequence.

If you need to enforce that traffic path, the right tool for the job is AWS Gateway Load Balancer (GWLB). It’s purpose-built to insert network services (like IDS, firewalls, or proxies) into your traffic flow in a scalable, managed way. Here’s how you’d set up your service chain with GWLB:

• Deploy your network services as targets: Create target groups for your IDS and firewall EC2 instances. You can configure the GWLB to route traffic through the IDS first, then pass it to the firewall target group before sending it to your web server.
• Route traffic to the GWLB: Update your VPC route tables (both inbound from the internet and any internal traffic) to point to the GWLB instead of directly to your web server’s subnet.
• Configure the service chain flow: Use GWLB’s listener rules and target group forwarding to define the sequence: traffic enters GWLB → sent to IDS instances → after inspection, IDS forwards traffic back to GWLB → GWLB routes to firewall instances → firewall forwards back to GWLB → finally, GWLB sends traffic to your web server.

Alternatively, if you want a more manual (less scalable) approach, you could use iptables on your instances to forward traffic between them. For example:

• Inbound traffic goes to the IDS instance first.
• Use iptables rules on the IDS to forward all inspected traffic to the firewall instance.
• Then the firewall uses iptables to forward traffic to the web server.
• You’d also need to make sure route tables are set to send traffic to the IDS first, and enable IP forwarding on each EC2 instance (sysctl -w net.ipv4.ip_forward=1). But this gets messy quickly if you need to scale instances or handle failover.

To recap: Traffic mirroring won’t meet your requirement for a mandatory service chain—stick with GWLB for a managed, scalable solution, or use iptables if you’re okay with a manual setup.

内容的提问来源于stack exchange，提问作者p4pe