Can I publish UDP ports instead of TCP?

Yes. By default, `-p` assumes TCP protocol. If you are running a game server or DNS server that requires UDP, you must specify it explicitly: `-p 53:53/udp`.

What happens if two containers are on the same Bridge Network; do I still need `-p` for them to talk to each other?

NO! This is a massive revelation. The `-p` flag is ONLY required to expose a container to the OUTSIDE physical world (your laptop's browser). Containers on the exact same Bridge Network can talk to ALL of each other's ports natively, even if you never use `-p` and never use `EXPOSE`.

How do I find out what random port Docker assigned when using `-P`?

You run `docker ps` and look at the 'PORTS' column. Alternatively, you can run `docker port ` which specifically prints out the active port mappings for that container.

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Advanced Connectivity (-p)

Master Docker port publishing. Understand the critical distinction between the `EXPOSE` instruction and the `-p` flag, how to solve port collisions during horizontal scaling, and how traffic moves from the Host OS into the Container namespace.

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