The shop's containers need their own network. An old legacy network is left over from a previous setup.

Create the network and check its driver:

docker network create shop
docker network ls

Start the catalog web server and the session store on it:

docker run -d --name catalog --network shop nginx:1.27
docker run -d --name sessions --network shop redis:7.4

See both containers and their IPs:

docker network inspect shop

Confirm a container on shop reaches catalog by name:

docker run --rm --network shop alpine:3.20 wget -qO- http://catalog

Remove the network nothing uses:

docker network rm legacy