Cannot connect to any external address from any containers

Hello,

We recently experienced an issue where we were unable to connect to any external resources from inside our containers. Connectivity between the containers was fine and we were able to reach these resources via IP and name from the host.

We have docker deployed across multiple hosts and it was the same on every container regardless of the host it was on. We restarted docker one host at a time and as we did so the containers on that host were able to connect to the external resources.

Any tips on what we can look for to understand how this happened?

We are using docker version 26.1.3 on RHEL based distros.

Thanks!

My guess is that you have another application that changed iptables rules and broke the routing to the outside world. When you restarted Docker, the iptables rules could be recreated.

This part of the documentation could be useful

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