FVS338 ProSafe VPN Firewall 50 Reference Manual
Introduction 1-3
v1.0, March 2008
Port Forwarding with NAT. Although NAT prevents Internet locations from directly
accessing the PCs on the LAN, the firewall allows you to direct incoming traffic to specific
PCs based on the service port number of the incoming request. You can specify forwarding of
single ports or ranges of ports.
Exposed Host (Software DMZ). Incoming traffic from the Internet is normally discarded by
the firewall unless the traffic is a response to one of your local computers or a service for
which you have configured an inbound rule. Instead of discarding this traffic, you can have it
forwarded to one computer on your network.

Autosensing Ethernet Connections with Auto Uplink

With its internal 8-port 10/100 switch, the FVS338 can connect to either a 10 Mbps standard
Ethernet network or a 100 Mbps Fast Ethernet network. Both the LAN and WAN interfaces are
autosensing and capable of full-duplex or half-duplex operation.
The firewall incorporates Auto UplinkTM technology. Each Ethernet port will automatically sense
whether the Ethernet cable plugged into the port should have a ‘normal’ connection such as to a
PC or an ‘uplink’ connection such as to a switch or hub. That port will then configure itself to the
correct configuration. This feature also eliminates the need to worry about crossover cables, as
Auto Uplink will accommodate either type of cable to make the right connection.

Extensive Protocol Support

The VPN firewall supp orts the Transmission Control Protocol/Internet Protocol (TCP/IP) and
Routing Information Protocol (RIP).
IP Address Sharing by NAT. The VPN firewall allows severa l networked PCs to share an
Internet account using only a single IP address, which may be statically or dynamically
assigned by your Internet service provider (ISP). This technique, known as NAT, allows the
use of an inexpensive single-user ISP account.
Automatic Configuration of Attached PCs by DHCP. The VPN firewall dynamic al l y
assigns network configuration information, including IP, gateway, and domain na me server
(DNS) addresses, to attached PCs on the LAN using the Dynamic Host Configuration Protocol
(DHCP). This feature greatly simplifies configuration of PCs on your local network.
DNS Proxy. When DHCP is enabled and no DNS addresses are specified, the firewall
provides its own address as a DNS server to the attached PCs. The firewall obtains actual DNS
addresses from the ISP during connection setup and forwards DNS requests from the LAN.
PPP over Ethernet (PPPoE). PPPoE is a protocol for connecting remote hosts to the Internet
over a DSL connection by simulating a dial-u p connection. This feature eliminates the need to
run a login program such as EnterNet or WinPOET on your PC.