twtech deep dive into Achieving Fixed-IP Setup while still Leveraging AWS WAF with Appllication Load Balancer (ALB)
Intro:
- By default, AWS WAF doesn’t provide a fixed (static) IP address, because it’s a managed service that sits in front of other AWS services such as CloudFront, API Gateway, or Application Load Balancer (ALB) — all of which use dynamic IP ranges managed by AWS.
- However, there are reliable architectural patterns to achieve a fixed-IP setup while still leveraging AWS
WAF protection.
Breakdown:
- The core Challenge,
- Solution Overview Options,
- Option 1: Use AWS Global Accelerator (Recommended)
- Option 2: Use CloudFront + WAF,
- Option 3: Use Third-Party or Self-Managed WAF with Fixed IPs,
- Comparison Summary of the options,
- Sample AWS Reference Architecture (Fixed IP WAF with ALB),
- twtech Key Takeaways.
The Core Challenge.
· When twtech associates AWS WAF with an Application Load Balancer (ALB), its clients
connect directly to the ALB’s DNS name.
· However, ALB IPs are ephemeral or subject to change without notice.
· This means twtech cannot directly whitelist those ALB IPs in firewalls or on-prem systems that require fixed IPs.
Solution Overview
These are the three main approaches to achieve a fixed IP WAF
setup in front of a Load Balancer:
Option
1: Use AWS
Global Accelerator (Recommended)
· Best practice and AWS-supported
Architecture:
- Clients
→ AWS Global Accelerator (with static IPs)
- Global
Accelerator →
Application Load Balancer (protected by AWS WAF)
- ALB → EC2 / ECS / Lambda backend
How AWS Global Accelerator works:
- Global Accelerator
provides two static anycast IPs
(IPv4) that don’t change.
- twtech
associates its ALB as the
endpoint behind it.
- twtech can
attach AWS WAF directly to
the ALB or
to a CloudFront
distribution if needed for global filtering.
- The
WAF filters requests, but twtech clients will always connect via that
fixed IPs.
Pros:
- True static
IP addresses.
- High
performance due to AWS’s edge network.
- Built-in
DDoS protection (via AWS
Shield Standard).
Cons:
- Additional
cost for Global Accelerator
(~$0.025 per
GB + endpoint charges).
Option
2: Use CloudFront + WAF
· Common for web apps (HTTP/HTTPS)
Architecture:
- Clients → CloudFront (with WAF)
- CloudFront → ALB → backend resources
Details:
- CloudFront integrates natively with AWS WAF.
- CloudFront has a fixed set of edge locations, but not static IPs (they come from AWS IP ranges).
- However, twtech can use AWS’s published IP ranges JSON to automate whitelisting (e.g., with firewall automation).
Pros:
- Tight WAF
integration.
- Edge caching
for better latency.
- Ideal for
HTTP/S traffic.
Cons:
- Not
fixed IPs, only predictable AWS IP ranges (need automation if twtech wants
firewall rules).
Option
3: Use Third-Party or
Self-Managed WAF with Fixed IPs
If AWS-native options don’t fit
twtech can deploy:
- A
reverse proxy or NGFW appliance (like
Fortinet, Palo Alto, or F5) in a public
subnet with Elastic IPs.
- Configure it
to forward traffic to your ALB,
and associate AWS WAF at
the ALB level.
Architecture flow:
Client → Elastic IP (Reverse Proxy/WAF VM) → ALB (AWS WAF) → Backend
Pros:
- Complete
control over IPs and rules.
- Flexible
architecture.
Cons:
- Increased
management overhead.
- Loses the
“fully managed” WAF advantage.
- Higher cost.
Comparison Summary for
the options
|
Approach |
Fixed
IPs |
Managed |
Performance |
Cost |
Best
Use Case |
|
Global Accelerator +
ALB + WAF |
✅ Yes |
✅ Fully managed |
🚀 Excellent |
💲💲 |
Enterprise, multi-region web apps |
|
CloudFront + WAF + ALB |
❌ No (AWS ranges) |
✅ Fully managed |
🚀 Excellent |
💲 |
Public web apps needing caching |
|
Self-managed proxy +
ALB + WAF |
✅ Yes |
❌ Manual |
⚙️ Varies |
💲💲 |
Custom or hybrid network setups |
Sample AWS Reference Architecture (Fixed IP WAF with ALB)
twtech
Key Takeaways
- WAF itself can’t provide static IPs — use Global Accelerator if twtech need fixed ingress points.
- CloudFront + WAF is ideal for global web traffic, not for strict IP requirements.
- Global Accelerator + WAF + ALB = fully managed, fixed IP, high performance solution.
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