The only two important columns are “Local address: port” and “process”. The later is what process is listening whille the former is the interface that process is listening on and the port.

So you see that I don’t have any process listening on any port other than 80 and 443 iin the host and the regular ones.

That said, you containers will still listen on the ports you want but only on a virtual network interface.

Basically you only need to publish ports 80 amd 443 on the container or pod you have your reverse proxy on. Other containers need to only be attached to the same network as you already did.

It is good you have solved you initial issue. However, as you say, your rules are too permissive. You should not publish ports from containers to the host. Your container ports should only be accessible over reverse-proxy network. Said otherwise <my domain>:3000 should not resolve to anything.

This can be simply acheive by not publishing any port on your service containers.

Here is an example of my VPS:

Exposed ports:

$ ss -ntlp
State                Recv-Q               Send-Q                             Local Address:Port                             Peer Address:Port              Process                                                  
LISTEN               0                    128                                      0.0.0.0:22                                    0.0.0.0:*                  users:(("sshd",pid=4084094,fd=3))                       
LISTEN               0                    4096                                     0.0.0.0:443                                   0.0.0.0:*                  users:(("conmon",pid=3436659,fd=6))                     
LISTEN               0                    4096                                     0.0.0.0:5355                                  0.0.0.0:*                  users:(("systemd-resolve",pid=723,fd=11))               
LISTEN               0                    4096                                     0.0.0.0:80                                    0.0.0.0:*                  users:(("conmon",pid=3436659,fd=5))                     
LISTEN               0                    4096                                  127.0.0.54:53                                    0.0.0.0:*                  users:(("systemd-resolve",pid=723,fd=19))               
LISTEN               0                    4096                               127.0.0.53%lo:53                                    0.0.0.0:*                  users:(("systemd-resolve",pid=723,fd=17))  

Redacted list of containers:

$ podman container ls
CONTAINER ID  IMAGE                                        COMMAND               CREATED        STATUS                 PORTS                                     NAMES
[...]
docker.io/tootsuite/mastodon-streaming:v4.3  node ./streaming      2 months ago   Up 2 months (healthy)                                            social_streaming
docker.io/eqalpha/keydb:alpine               keydb-server /etc...  2 months ago   Up 2 months (healthy)                                            cloud_cache
localhost/podman-pause:4.4.1-1111111111                            2 months ago   Up 2 months            0.0.0.0:80->80/tcp, 0.0.0.0:443->443/tcp  1111111111-infra
docker.io/library/traefik:3.2                traefik               2 months ago   Up 2 months            0.0.0.0:80->80/tcp, 0.0.0.0:443->443/tcp  traefik
docker.io/library/nginx:1.27-alpine          nginx -g daemon o...  3 weeks ago    Up 3 weeks                                                       cloud_web
docker.io/library/nginx:1.27-alpine          nginx -g daemon o...  3 weeks ago    Up 3 weeks                                                       social_front
[...]