How do I make Synology Diskstation port visible to computer for Docker app

I have a Docker app running on a Synology DS218+

But the app runs on port 4567 not visible from my PC (I can access Synology DSM on port 5000 from my PC okay).

How do I resolve this, I am not clear whether I have to configure something in the Docker container or within Synology DSM Control Panel itself. The Synology is brand new, with only the defaults and Docker installed, I have not enabled the Synology Firewall.

The DockerFile is

FROM openjdk:8-jre-alpine

RUN apk add --no-cache ca-certificates curl tini \
 && mkdir -p /opt \
 && curl http://www.jthink.net/songkong/downloads/current/songkong-linux-headless-novm.tgz?val=77 | tar -C /opt -xzf - \
 && find /opt/songkong -perm /u+x -type f -print0 | xargs -0 chmod a+x

RUN addgroup -S songkong \
 && adduser -S -G songkong songkong

USER songkong:songkong

EXPOSE 4567

ENTRYPOINT ["/sbin/tini"]

# VOLUME /opt/songkong/songkong.properties

# preferences and match database are stored here
VOLUME /home/songkong/.songkong

WORKDIR /opt/songkong

CMD /opt/songkong/songkongremote8.sh

Solution

Turned out to be easy to do

Launch Image
Select Advanced Settings
Go to Network tab
Enable Use the same network as Docker host
Apply setting and continue to launch Container

Does seem to me this should be enabled by default since running a container with Synology invisible to any computer outside of Synology doesnt seem very useful

There is also a more flexible but more slightly complex solution using the Port Forwarding tab.