About Gateway

Hi,
I am using Windows 98 SE OS.And i installed DLink Server for internet sharing.My DLink server ip is 192.168.50.1 and my clients IP are 192.168.50.10 to 192.169.50.25.On my clients i assigned 192.168.50.1 as a gateway.Now when my users write http://192.168.50.1 the dlink server administration part will open.I want to restrict my users.I want when my users write this IP the administration page won’t open but they can access internet.How i do it.
Anurag.