I’m facing a very tough problem. I’m setting up a docker daemon on an ubuntu server located inside an isolated network of my university. Docker is meant to run containers for gitlab and sharelatex.
As soon as I install docker, connections initiated by the intranet won’t get answered by the server anymore. Connections initiated from the internet always work. Completely removing docker and rebooting the system makes intranet connections working again. Besides docker, nginx is installed on the host system. While docker is installed, incoming port 80 packets can be observed passing the port. But these packets won’t make it to nginx, as the access.log doesn’t show any related logs concerning the http requests.
What docker configuration could cause the intranet packets to be dropped?
I flushed policies and chains made by docker on the iptables. That didn’t help either. I also tried to disable that docker doesn’t edit the iptables at all. There are no further rules and policies specified in the iptables. So there is no firewall rejecting any connections.
I’m thankful for any help!