Loopback and Private IPv4 address forwarding

I have a linux server (Ubuntu 16.04) with a loopback interface ( and a physical interface with a private ipv4 address (

I installed docker swarm and I create a cluster with a single node:

docker swarm init --advertise-addr

Then I created a service, for example nginx:

docker service create -p 8080:80 nginx

Now if I request the service from the private address, the service is reachable:

$ curl

But if I request the service from the loopback address, it isn’t reachable:

$ curl

I think that I should forward the services on the private IPv4 address to the loopback, but I don’t know what is the best way to accomplish it.