Adding a host I immediately lose connection to IP

I am using ESXi (6.x) and when I add a host (custom host) to the environment (it happens on both Kubernetes and Cattle), I lose the connection to the host a few seconds/minutes after this happens. I never get it back. If I reboot and Docker is not running, then I can login via SSH and ping that host. The second I start up the agent again, it goes away.

However, from the controller (WebUI), if I ping or SSH to the hosts that I cannot get to, I can get to the hosts via other systems in the VLAN. So, for example, from the Controller system (WebUI), I can SSH to them, just not from my computer.

I know its not our firewall in the office, since killing docker and rebooting fixes the issue.

We use ESXi and have an internal IP address, for example: 10.50.50.x; this is the only IP that is assigned to the system. Again, I can access this system regardless, but once I run the container to set this VM up as a rancher host, I lose the connection.

It seems like an IPTables thing that rancher is doing that is causing me to be blocked.

Has anyone else experienced this?

Software Versions:
Docker: 1.12.6
Rancher: 1.5.7 and 1.6.0 (tested on both)
OS: RHEL 7.3
Hypervisor: ESXi 6.x


If it’s network related I would like to know what subnet you are connecting from where the connection is being dropped? If the host is fine (no high CPU/disk/network load) and only that connections gets dropped then that would be the only thing that could go wrong I would say.