Welcome App not responding - Cyphernode in Docker swarm mode - Host in 10.0.0.X range

[phillamy]

After setup, the welcome app is not responding.

• When trying to browse from a remote host (https://10.0.0.X:443/welcome), the browser times out.
• When trying to curl from a remote host(curl -k https://10.0.0.X/welcome), the request times out. The same command on the host works and returns a HTTP 403 as expected

The problem is caused by an IP address conflict. The host has an address in the 10.0.0.X range. Docker swarm uses adresses in the same address pool/range for its subnet.

From Docker docs (2021-06): https://docs.docker.com/engine/swarm/swarm-mode/

By default Docker Swarm uses a default address pool 10.0. 0.0/8 for global scope (overlay) networks. Every network that does not have a subnet specified will have a subnet sequentially allocated from this pool.

To fix this, the swarm could be initialized with a different address pool during setup:

docker swarm init --default-addr-pool <IP range in CIDR>

[Kexkey]

Thanks for the report!

Even if it sounds like it's not Cyphernode-related, I guess it would be possible to detect that situation during Cyphernode's setup and mitigate by changing the Swarm's address pool... or at least display a message to the user.

Thanks for documenting here. This issue might save a lot of time to others in the future.