if its a server you should specify one, DHCP for a server is not really a good idea
chances are its one higher or lower than your windows machine so you could try to ping likely addresses like so
windows: 192.168.1.100 so if you linux machine came up after it would be 192.168.1.101 if it came up before it would be 192.16.1.99
of course your IP addresses could be a differant format but if you really wanted to know for sure just plug a keyboard into the linux machine and login then do /sbin/ifconfig