Two containers, web (nginx) and cache (Redis), run on the default bridge with no published ports. Map the network.

List the networks and inspect bridge:

docker network inspect bridge

Note the Subnet and Gateway under IPAM.Config, and the containers under Containers.

Read web's IP directly:

docker inspect --format '{{.NetworkSettings.IPAddress}}' web

curl localhost fails because web publishes nothing. Fetch the page by IP instead and save it:

curl -s 172.17.0.2 > ~/web.html

Finally, try to reach web by name from another container on the default bridge:

docker run --rm alpine:3.20 ping -c 1 web