User's Manual Part 2
Release8PlanningGuide
Issue2,November2007 Draft5forRegulatoryReview 156
13.3 NETWORKADDRESSTRANSLATION(NAT)
13.3.1 NAT,DHCPServer,DHCPClient,andDMZinSM
The Cyclone system provides NAT (network address translation) for SMs in the following
combinations of NAT and DHCP (Dynamic Host Configuration Protocol):
• NAT Disabled (as in earlier releases)
• NAT with DHCP Client and DHCP Server
• NAT with DHCP Client
• NAT with DHCP Server
• NAT without DHCP
NAT
NAT isolates devices connected to the Ethernet/wired side of an SM from being seen
directly from the wireless side of the SM. With NAT enabled, the SM has an IP address
for transport traffic (separate from its address for management), terminates transport
traffic, and allows you to assign a range of IP addresses to devices that are connected
to the Ethernet/wired side of the SM.
In the Cyclone system, NAT supports many protocols, including HTTP, ICMP (Internet
Control Message Protocols), and FTP (File Transfer Protocol). For virtual private network
(VPN) implementation, L2TP over IPSec (Level 2 Tunneling Protocol over IP Security) is
supported, but PPTP (Point to Point Tunneling Protocol) is not supported. See NAT and
VPNs on Page 161.
DHCP
DHCP enables a device to be assigned a new IP address and TCP/IP parameters,
including a default gateway, whenever the device reboots. Thus DHCP reduces
configuration time, conserves IP addresses, and allows modules to be moved to a
different network within the Cyclone system.
In conjunction with the NAT features, each SM provides
• a DHCP server that assigns IP addresses to computers connected to the SM by
Ethernet protocol.
• a DHCP client that receives an IP address for the SM from a network DHCP
server.
DMZ
In conjunction with the NAT features, a DMZ (demilitarized zone) allows the assignment
of one IP address behind the SM for a device to logically exist outside the firewall and
receive network traffic. The first three octets of this IP address must be identical to the
first three octets of the NAT private IP address.