Limit Droplet traffic to DO Load Balancer

Posted July 31, 2018 2.5k views
FirewallLoad BalancingUbuntu 16.04

I have a DO load balancer in front of two droplets. I want to be able to restrict traffic using ufw on the droplets to only allow traffic from the load balancer.
My app listens for HTTP on port 8001 so I’ve tried using the following:
sudo ufw allow from <publicIpOfLB> to any port 8001

Where <publicIpOfLB> is the public IP address shown on the load balancer config page

However, I assume the load balancer traffic isn’t seen to be coming from the public IP address and so this rule doesn’t allow the traffic through but I can’t see any other address to use. Any ideas how to achieve this?

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1 answer

Hello friend!

In this case you might actually block the port on the public IP and that should be the shortest path to solve it. The LB does bring traffic in through a private interface.

Kind Regards,