I've got a situation where I need to communicate to a device connected to a Lantronix MSS485 converter (allows RS485 devices to be connected to a network). Normally the converter would get assigned a fixed IP, but I've got a situation where the customer has a DSL connection to the Internet with dynamic IP. Although the converter box can be configured with DHCP, I still have the problem of not being able to communicate w/ the converter as I don't know the IP. I've suggested installing a firewall/router and enabling DHCP and NAT on it, thus allowing me to keep the network address on the LAN fixed (but still allow connecting to the Internet through the DSL), but the customer isn't going for that. Anyway... Is there a way to identify the IP address of a device given something fixed, like the MAC address?