this post was submitted on 29 Aug 2025
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Docker docs:

Docker routes container traffic in the nat table, which means that packets are diverted before it reaches the INPUT and OUTPUT chains that ufw uses. Packets are routed before the firewall rules can be applied, effectively ignoring your firewall configuration.

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[–] communism@lemmy.ml 2 points 6 days ago (3 children)
[–] qaz@lemmy.world 1 points 6 days ago (2 children)

That caused issues with Docker containers being unable to communicate with eachother for me.

[–] tux7350@lemmy.world 2 points 6 days ago (1 children)

Did you allow the containers to talk to eachother with ufw after setting it up?

[–] qaz@lemmy.world 2 points 6 days ago

Yes, you can fix it by doing this

echo "Adding rules for Docker subnets to allow communication between containers..."
for subnet in $(docker network inspect bridge -f '{{range .IPAM.Config}}{{.Subnet}} {{end}}'); 
    sudo ufw allow from $subnet
    echo "Added rule for $subnet"
done