IP Setup 4-5NAT guidelinesObserve the following guidelines when using NAT.n Only one node per internal network can supply a specificservice. In our example, if there is more than one web serveron the 10.0.0.0 network, the Netopia ISDN Router would not beable to differentiate incoming web traffic destined for each webserver. Similarly, external users cannot ping internal nodes,although the Netopia ISDN Router can respond to pingrequests.As mentioned earlier, you can enable NAT on one connection profile,disable it on another, and use the two profiles simultaneously. Theprofiles might have the following attributes:n A “normal” profile connects to your branch or main office. Yourcompany network administrator has assigned you a local IPaddress range that is consistent with the address spaceassigned to your company so that you seamlessly integratewhen connected. The remote IP address and mask for thisprofile define only the company’s address space, so that theonly IP traffic you send over this connection is for hosts andservers within your company.n A NAT profile connects to the internet via an ISP. Even thoughthe ISP assigns you a dynamic address each time you connect,there will be no conflict of address spaces, since NAT makesthe corporate address you use locally invisible to the ISP. Youenter the ISP’s remote IP address as your default IP gateway sothat any IP traffic not intended for your corporate intranet will bedirected to the ISP.n Associate your primary Domain Name Server with whicheverprofile is more accessable. If you choose for neither profile tobe “dial-on-demand”, you may associate a secondary DNS withthe other profile.
