when using remote mode, the client side needs to set --local_ip

Otherwise, the server and client sides will generate random local ip addresses independently, thus, the server side sends the packet will not match the IP address of the device of client side, and the packetdrill will hang for waiting the SYN-ACK packet for each connections.

I try this on my laptop with two VMs residing in a same LAN, e.g. both devices are under the same bridge.