VPN on NT4 Problem

I have setup MSVPN on the server, and the clients (1 win2k, and 1 win 98). The clients can get their connection to the server. The server is assigning the ip addresses for the clients via the Remote Access Service. Here is the problem. The clients get a ip address 192.168.1.x with a mask of 255.255.255.255, the server has the ip address 192.168.1.1 with a mask of 255.255.255.0. Why are the 2 getting different masks?