DSL LAN Extender 200 User’s Guide
© 2002 Black Box Corporation
Page 38
Case (F) DSL LAN Extender CPs NAT enabled, some using private IP, some using public
IP
As shown in the example on next page, the client side computers are assigned to two groups: group PC_S
using public IP addresses in subnetwork 194.1.2.x; and group PC_A using private IP addresses in
subnetwork 192.168.1.x, using private IP addresses. The routing functions built into the DSL LAN
Extender
CP supports the following:
•
Group PC_A and group PC_S talking to each other using TCP/IP protocol
•
The DSL LAN Extender CP supports two IP subnetworks simultaneously on the single Ethernet port
Besides, because the two groups are sharing the same physical Ethernet bus, other protocols (e.g.
NetWare, NetBEUI) will automatically work.
If the site wants to host its own Web server or e-mail server, the servers should be assigned in the group
of public IP addresses (i.e. PC_S) if possible. This way, the IP address of the servers does not need to be
translated, as it does for a private IP, and therefore this way has a little performance gain.
If it’s not possible to assign a public IP to the Web server or e-mail server, users can still assign them a
private IP. In this case, users need to enter these servers’ IP addresses to the proper entries using the DSL
LAN Extender
console user interface.
Network Structure:
ISP assigns IP addresses 194.1.1.1 to 194.1.1.7 to the customer site
Customer site is NAT enabled, some machines using private IP addresses in subnetwork 192.168.1.0;
others, preferably servers, are using public IP addresses.
Customer Site Capabilities:
Every machine in the chart can access the Internet.
The e-mail server (using public IP 194.1.2.2) can be accessed from both inside and outside.
The Web server (using private IP 194.1.2.3) can be accessed from both inside and outside.
All machines in site A can talk any other protocols (NetBEUI, NetWare, AppleTalk) among themselves.
Configurations:
All DSL LAN Extenders have RIP enabled.
In CP_A, the Web server is set as address 0.0.0.0 because it has a public IP. The mail server has a
private IP, 192.168.1.10.
Register through DNS is the Web server as 194.1.2.3.
Example Traffic Path:
PC_A1 sends a packet to the Internet: PC_A1
→
CP_A
→
CO_A
→
WAN Router
→
Internet
PC_S1 sends a packet to the Internet: PC_S1
→
CP_A
→
CO_A
→
WAN Router
→
Internet
