Netopia 2200 - Manual (Page 87)

87
Configure
With this topology, you configure the embedded administration por ts as a first task, fol-
lowed by the Pinholes and, finally, the NAT Default Ser ver.
When using both NAT pinholes and NAT Default Ser ver the Gateway works with the follow-
ing rules (in sequence) to for ward traffic from the Internet to the LAN:
1. If the packet is a response to an existing connection created by outbound
traffic from a LAN PC, forward to that station.
2.
If not, check for a match with a pinhole configuration and, if one is found,
forward the packet according to the pinhole rule.
3.
If there’s no pinhole, the packet is forwarded to the Default Server.
IP-Passthrough. Your Gateway offers an IP passthrough feature. The IP passthrough
feature allows a single PC on the LAN to have the Gateway’s public address assigned to it.
It also provides PAT (NAPT) via the same public IP address for all other hosts on the private
LAN subnet. Using IP passthrough:
• The public WAN IP is used to provide IP address translation for private LAN computers.
• The public WAN IP is assigned and reused on a LAN computer.
• DHCP address ser ving can automatically ser ve the WAN IP address to a LAN computer.
When DHCP is used for addressing the designated passthrough PC, the acquired or
configured WAN address is passed to DHCP, which will dynamically configure a single-
ser vable-address subnet, and reser ve the address for the configured MAC address.
This dynamic subnet configuration is based on the local and remote WAN address and
subnet mask. If the WAN inter face does not have a suitable subnet mask that is
usable, for example when using PPP or PPPoE, the DHCP subnet configuration will
default to a class C subnet mask.
• If you want to manually assign the WAN address to a LAN PC, do not check the DHCP
Enable checkbox.
• If you check the DHCP Enable checkbox, the screen expands.