Port mapping works for IPv6 but not IPv4

[floeschie]

Hi all,

I’m running a Minecraft server instance as 1 click app.

The port mapping works for my public IPv6 but not for my public IPv4 address. This makes Minecraft clients think the server is unreachable.

When running lsof -i, I see the Minecraft server port being opened on IPv6, but not n IPv4. I was expecting ports to be mapped to both IPv6 and IPv4.

I’m not a Docker guru, so maybe someone can point me to right place to look at or give me a hint? Is this a CapRover or Docker configuration thing?

• RAM: 7.76 GB
• OS: Ubuntu Linux
• CPU: 4 cores
• Architecture: x86_64
• Docker Version: 23.0.5

Any help highly appreciated!

Florian

[githubsaturn]

This is not CapRover, it's Docker. CapRover simply passes down the ports to Docker.

And Docker automatically binds all network interfaces unless you have a specific Docker/netowrk configuration on your machine.

What do you see when you run lsof -i | grep 3000 ?

[floeschie]

Hi @githubsaturn,

thanks for your quick reply. This is what lsof prints:

# lsof -i | grep 3000
docker-pr  1416            root    4u  IPv4  23242      0t0  TCP *:3000 (LISTEN)

[floeschie]

Thanks again!

With service override, the Minecraft server's port 19132 is exposed via IPv4, and IPv4 only:

# lsof -i | grep 19132
docker-pr 52339            root    4u  IPv4 428024      0t0  TCP *:19132 (LISTEN)
docker-pr 52352            root    4u  IPv4 428729      0t0  UDP *:19132

I'm wondering if there is a way to bind port 19132 to IPv4 and IPv6?

[githubsaturn]

Try changing publish mode to "ingress" and see if it helps

[floeschie]

When I use "host", then it uses IPv4 only.
When I use "ingress", it uses IPv6 only.

[githubsaturn]

This is a Docker question at this point, you can submit your case on Docker's github issues

[floeschie]

OK, thanks for helping me narrowing down the topic!