How to restrict access to your website hosted in AKS with simple trick

I use AKS to host websites at work.

We route all traffic to website using a single NGINX pod. There is a service associated with this pod which is open to public. This is how we restrict access. You can use single IP with /32 at the end or add more with subnetting

apiVersion: v1
kind: Service
metadata:
  name: ui-server
spec:
  type: LoadBalancer
  ports:
  - port: 80
  selector:
    app: ui-server
  loadBalancerSourceRanges:
  - 172.172.127.72/32
  - 172.172.127.80/32

In the above snippet, we have allowed access to only 2 IPs