IP Setup and Network Address Translation
Just as an IP address specifies a particular computer on a network, ports are addresses that specify a particular service in a computer. There are many universally
■Web servers typically use port number 80
■All FTP servers use port number 21
■Telnet uses port number 23
■SNMP uses port number 161
To help direct incoming IP traffic to the appropriate server, the Netopia R7200 lets you associate these and other port numbers with distinct IP addresses on your internal LAN using exported services. See “IP setup” on page
Advanced IP/IPX router configuration options
Advanced users can optionally use connection profiles to configure the IP and IPX protocol stack interfaces on the SDSL link. You need not explicitly define these parameters, however. The following information is provided as reference to the possible router configurations advanced users may desire.
The IP router interface on the SDSL link:
■may be numbered or unnumbered.
■may or may not use Network Address Translation (NAT).
■will attempt to autoconfigure itself without an explicitly configured connection profile, if permitted to do so by the setting of the Must Match a Defined Profile item in the Default Profile screen. See “The default profile” on page
The link up process at the interface between the SDSL data link encapsulation module and the IP router functions as follows:
■When the SDSL data link comes up, the router will search for a configured connection profile that specifies SDSL encapsulation.
■If more than one SDSL profile exists, the router will use the first such profile.
■If no SDSL profile exists, and the Must Match a Defined Profile field in the Default SDSL Profile is set to No, the router will construct a Default Profile, and the link up process will continue using this constructed profile as if it were an explicitly configured one.
■If no SDSL profile exists, and the Must Match a Defined Profile field in the Default SDSL Profile is set to Yes, IP will not come up on the SDSL link. The router will log an “IP connection refused” event in the WAN Event History.
■If an SDSL profile exists (or a default one has been constructed), the router will attempt to configure its interface on the SDSL link using the information stored in the profile.
