hole punching is best for clients behind a NAT. if the client has a static public IP and nothing (ie firewall) is blocking UDP traffic turn off hole punching. If multiple clients are on the same lan behind NAT, hole punching will not work well. Best solution, give each device a different listening port and set up port forwarding on the NAT device. If port forwarding is not an option, only set up one client using hole punching and and make it an egress gateway for the other devices on the lan. If you absolutely need more than one client, don't use hole punching and live with the limitation that network interaction must be iniated from from the NATed device. In this case, if you have a similar setup behind a different NAT, there is a strong possibility that the devices behind the first NAT will not be able to communicate with the devices behind the second NAT.