User manual

4200 User Manual Edgewater Networks, Inc.
Version 2.2 24
Data Networking Configuration
The 4200 provides static IP routing and two types of Network Address Translation
(NAT) functions for data traffic. This chapter explains the use and configuration of
these features.
NAT for Data Traffic
NAT allows hosts on a private internal network
(the LAN side of the 4200) to anonymously
communicate with devices on an external
network (the WAN side of the 4200). The 4200
with NAT enabled will re-write outbound packet
headers using public IP addresses in place of
private IP addresses so that the private IP
addresses are not exposed to the external
network. Additionally, the ports used by the IP
addresses are also changed as they traverse the
4200. This is known as Port Address
Translation(PAT) and provides an additional
security measure. The 4200 maintains a table
of these mappings so that return packets can be
forwarded to the correct host on the private
network.
The 4200 provides two types of NAT functions: dynamic NAT and static NAT.
Dynamic NAT allows many private IP addresses to be mapped to a single public IP
address (using different port numbers of the public IP address). Static NAT maps
private IP addresses and port numbers to public IP addresses and port numbers on a
one-to-one basis.
PLEASE note: The 4200 ALG automatically handles NAT for voice devices as
described in Chapter 3 “VoIP Configuration”.
Configure Dynamic NAT
Use Dynamic NAT when you have multiple PCs installed on the LAN side of the 4200
that require Internet or WAN access. Once Dynamic NAT is enabled the 4200 will
automatically perform an address translation for all packets to/from the LAN side
PCs.
A. Select NAT.
The default value for dynamic NAT is enabled.
B. Use the Enable Lan NAT checkbox to enable or disable dynamic NAT.
C. Press Submit.
Configure Static NAT
Use Static NAT when a server or PC located in the private network needs to be
accessible from the external network. Some examples include a corporate web
server, a mail server or an FTP server. In these instances, the 4200 statically maps