A Reliable way to Identify a computer by its ip address

I have a network of computers that they wi开发者_如何转开发ll connect to the a server with DHCP, so I don't know what Ip address a computer will get when I connects to the server. If 192.168.0.39 for example is connected to the server can I identify the real computer behinde this ip address? ( I can install an external application on each client in order to send some data to server for example mac address or so... )

If you are responsible for the DHCP server, you can configure it to hand out a specific IP to a specific MAC. Having done that, you can be reasonably confident of that mapping -- it is possible to spoof MACs, so if you are worried about security, you'll need a much more heavy duty approach. If this is a casual application where the risk of that is low, you configure your DHCP server to hand out IPs based on MACs and then make use of those mappings in your application.

You might not even need the IP address. On an Ethernet network, all communication from a computer, whether it's IPv4, IPv6, or even IPX will be labelled with a MAC address that's stable over time and unique per network card.