How to forward client IP address from CloudFlare to Kubernetes NGINX ingress controller?

Question

I'm using CloudFlare as DNS server for the system and need of whitelist IP for some domains of the system. I managed to do this but when I enable Proxy status feature for domain on CloudFlare I get 403 Forbidden error because CloudFlare forwards its own IP for ingress instead of client IP address.
I found a tutorial here .
Is there any other way to solve this problem?
Here is the CloudFlare configuration.

Here is the ingress configuration.

apiVersion: networking.k8s.io/v1
kind: Ingress
metadata:
  name: admin-ingress
  namespace: machine-learning
  labels:
    app.kubernetes.io/managed-by: Helm
  annotations:
    nginx.ingress.kubernetes.io/proxy-body-size: 50m
    nginx.ingress.kubernetes.io/whitelist-source-range: 184.90.9.99,183.88.6.88
spec:
  rules:
    - host: "admin.xxx.com"
      http:
        paths:
          - path: /
            pathType: ImplementationSpecific
            backend:
              service:
                name: admin-service
                port:
                  name: http

And this is the error I get

Any contribution is greatly appreciated.
Best regards,

Answer 1

Please add this line real_ip_header CF-Connecting-IP; in your Nginx config file to forward the original client IP address to the server.

Answer 2

try this https://github.com/kubernetes/ingress-nginx/blob/main/docs/user-guide/nginx-configuration/annotations.md#configuration-snippet

nginx.ingress.kubernetes.io/configuration-snippet: |
  real_ip_header CF-Connecting-IP;