Internet Connection

[flightsupport]

I maintain a Network that utilizes a Novell File Server. Internet connection is provided via a Windows 2000 "RAS" server...analogue connection. There are 31 Windows 98 clients on the network. The "RAS" server has the Windows 2000 dial up connection shared, which [usually] allows all 31Windows 98 clients to access the internet - http, SMTP. POP, FTP, PING - the standard protocols. However, I have intermittent connection problems: for no reason, and without making any changes to the network configuration, one or more of the clients will cease to recognize the internet connection. While trouble shooting this phenomenon, I ascertain that all original configurations are unchanged. I can find no logical reason why these clients (not always the same clients, either) have stopped seeing the internet connection. I have attempted to make use of Proxy software (WinRoute) and over time, I experience the same dilemma. The 'problem' eventually fixes itself...after a period of any where between 2 hours and two weeks. Can anyone understand what suddenly (and randomly) causes the clients to stop seeing the "RAS" server? And then correct the problem?

Config:
DHCP ("RAS" Server) - Static IP 192.168.0.1 {Windows 2000}
Clients - obtain IP automatically (dynamically), default gateway=192.168.0.1, primary DNS=192.168.0.1 {Windows 98}