Netopia 2200 - Manual (Page 343)

343
Security
IP-Passthrough
Netopia OS now offers an IP passthrough feature. The IP passthrough feature allows a sin-
gle 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.
VPN IPSec Pass Through
This Netopia ser vice suppor ts your independent VPN client software in a transparent man-
ner. Netopia has implemented an Application Layer Gateway (ALG) to suppor t multiple PCs
running IP Security protocols.
This feature has three elements:
1.
On power up or reset, the address mapping function (NAT) of the Gate-
way’s WAN configuration is turned on by default.
2.
When you use your third-party VPN application, the Gateway recognizes
the traffic from your client and your unit. It allows the packets to pass
through the NAT “protection layer” via the encrypted IPSec tunnel.
3. The encrypted IPSec tunnel is established “through” the Gateway.
A typical VPN IPSec Tunnel pass through is diagrammed below:
Netopia
Gateway