# Openstack neutron could not load ... InterfaceDriver warnings are.. mostly harmless

I’ve been working on an OpenStack lab, and one of the (many) issues I encountered was that my instances (VMs) wouldn’t get their DHCP addresses from the neutron controller.

This ended up being due to the fact that I’d built CentOS 7 off a security-focused kickstart which set the IPTables FORWARD policy to “DROP” (a bad idea for an OpenStack node, along with SELinux and umask changes).

Before I reached this conclusion, in the process of debugging, I discovered the following disturbing error messages from stevedore.named in linuxbridge-agent.log:

Could not load neutron.agent.linux.interface.BridgeInterfaceDriver

So, if you encounter this error, but your DHCP agent is still running per neutron agent-list, ignore it and look for your problem elsewhere :)