Docker listening on port 8888 after latest update; no running containers

Docker Desktop
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I’m a bit perplexed by this. I just updated Docker to the latest 4.35.0, running on Windows 11, and after that I found that one of my containers which was configured to listen on port 8888 kept returning 404 not found error. After quite some digging I actually realized it wasn’t the container that was listening on that port. I stopped all containers, and port 8888 was still listening and responding with 404.

netstat reports the PID listening on this port corresponds to “com.docker.backend.exe” running as my user. Again, this happens when all containers are stopped. I don’t know why Docker all of a sudden binds to this port when previously it clearly did not. Any ideas?

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What was your previous Docker DEsktop version in which port 8888 still worked?

It looks like Docker Desktop uses it for an internal purpose, but I don’t know for what. It does on my macOS and my Windows as well…

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Unfortunately, I don’t remember what my previous version was, I think it was a couple of months since I last updated :-/

I don’t mind that it uses the port internally, but I’m surprised because I can’t find any documentation on that, and the opposite: I see many examples of containers binding to that port…

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I found what used it. It turned out that port is used only when “Send usage statistics” is enabled in General Docker Desktop settings. I don’t know why sending usage statistics requires listening on a local port, but if you disable it, your container can use the port again. If you disabled it before, maybe it was reenabled when you upgraded Docker Desktop.

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Thank you!! Strange, because I never explicitly enabled or disabled it, so possibly it just changed default values between updates. Thanks again :slight_smile:

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Thank you for the suggestion!!
I ran into this issue in the middle of the demonstration on a meeting) Disabling “Send usage statistics” worked for me too.

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This caused major havoc at my place of work for 2 days before I finally stumbled upon this post.
I do not understand why it just fails silently when starting a container using that port, instead of throwing an error trying to bind that port!

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Yeah this should probably be rolled back since I think 8888 is a common port that developers use for application hosting.

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Because it binds on IPv6, so it silently rips off your legs and leaves you hanging dry :sleepy:

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You mean for listening on port 8888? If it were the case you wouldn’t have a problem with connecting to localhost:8888, but I don’t know why it was chosen. I often use ports like this for testing. Sometimes port 9999. It is unexpected but not a problem to me. You could report it in the github repositories like

or

or

I don’t know a common place to report for all platforms. In the meantime I’m trying to learn more about this port.

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This is now resolved with v4.35.1

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