Nat Guidelines - Netopia 435 Reference Manual

NAT guidelines

Observe the following guidelines when using NAT.
Only one node per internal network can supply a specific
service. In our example, if there is more than one web server
on the 10.0.0.0 network, the Netopia ISDN Router would not be
able to differentiate incoming web traffic destined for each web
server. Similarly, external users cannot ping internal nodes,
although the Netopia ISDN Router can respond to ping
requests.
As mentioned earlier, you can enable NAT on one connection profile,
disable it on another, and use the two profiles simultaneously. The
profiles might have the following attributes:
A "normal" profile connects to your branch or main office. Your
company network administrator has assigned you a local IP
address range that is consistent with the address space
assigned to your company so that you seamlessly integrate
when connected. The remote IP address and mask for this
profile define only the company's address space, so that the
only IP traffic you send over this connection is for hosts and
servers within your company.
A NAT profile connects to the internet via an ISP. Even though
the ISP assigns you a dynamic address each time you connect,
there will be no conflict of address spaces, since NAT makes
the corporate address you use locally invisible to the ISP. You
enter the ISP's remote IP address as your default IP gateway so
that any IP traffic not intended for your corporate intranet will be
directed to the ISP.
Associate your primary Domain Name Server with whichever
profile is more accessable. If you choose for neither profile to
be "dial-on-demand", you may associate a secondary DNS with
the other profile.
IP Setup 4-5